diff --git a/src/modules/Elsa.Alterations.Core/Contracts/IAlterationPlanManager.cs b/src/modules/Elsa.Alterations.Core/Contracts/IAlterationPlanManager.cs
index 79b72c6d9..617cf2824 100644
--- a/src/modules/Elsa.Alterations.Core/Contracts/IAlterationPlanManager.cs
+++ b/src/modules/Elsa.Alterations.Core/Contracts/IAlterationPlanManager.cs
@@ -2,9 +2,23 @@ using Elsa.Alterations.Core.Entities;
 
 namespace Elsa.Alterations.Core.Contracts;
 
+/// <summary>
+/// Represents a manager for alteration plans.
+/// </summary>
 public interface IAlterationPlanManager
 {
+    /// <summary>
+    /// Gets an alteration plan by ID.
+    /// </summary>
     Task<AlterationPlan?> GetPlanAsync(string planId, CancellationToken cancellationToken = default);
+    
+    /// <summary>
+    /// Gets a value indicating whether all jobs in the plan have been completed.
+    /// </summary>
     Task<bool> GetIsAllJobsCompletedAsync(string planId, CancellationToken cancellationToken = default);
+    
+    /// <summary>
+    /// Completes an alteration plan.
+    /// </summary>
     Task CompletePlanAsync(AlterationPlan plan, CancellationToken cancellationToken = default);
 }
\ No newline at end of file
diff --git a/src/modules/Elsa.Alterations/AlterationHandlers/CancelActivityHandler.cs b/src/modules/Elsa.Alterations/AlterationHandlers/CancelActivityHandler.cs
index 05f58d16b..95ffa2db7 100644
--- a/src/modules/Elsa.Alterations/AlterationHandlers/CancelActivityHandler.cs
+++ b/src/modules/Elsa.Alterations/AlterationHandlers/CancelActivityHandler.cs
@@ -1,9 +1,8 @@
 using Elsa.Alterations.AlterationTypes;
 using Elsa.Alterations.Core.Abstractions;
 using Elsa.Alterations.Core.Contexts;
+using Elsa.Extensions;
 using Elsa.Workflows;
-using Elsa.Workflows.Runtime.Contracts;
-using Elsa.Workflows.Runtime.Filters;
 using JetBrains.Annotations;
 
 namespace Elsa.Alterations.AlterationHandlers;
@@ -14,20 +13,6 @@ namespace Elsa.Alterations.AlterationHandlers;
 [UsedImplicitly]
 public class CancelActivityHandler : AlterationHandlerBase<CancelActivity>
 {
-    private readonly IBookmarkManager _bookmarkManager;
-    private readonly IActivityExecutionManager _activityExecutionManager;
-    private readonly IActivityExecutionMapper _activityExecutionMapper;
-
-    /// <summary>
-    /// Initializes a new instance of the <see cref="CancelActivityHandler"/> class.
-    /// </summary>
-    public CancelActivityHandler(IBookmarkManager bookmarkManager, IActivityExecutionManager activityExecutionManager, IActivityExecutionMapper activityExecutionMapper)
-    {
-        _bookmarkManager = bookmarkManager;
-        _activityExecutionManager = activityExecutionManager;
-        _activityExecutionMapper = activityExecutionMapper;
-    }
-
     /// <inheritdoc />
     protected override ValueTask HandleAsync(AlterationContext context, CancelActivity alteration)
     {
@@ -49,32 +34,19 @@ public class CancelActivityHandler : AlterationHandlerBase<CancelActivity>
             return ValueTask.CompletedTask;
         }
 
-        context.Succeed(() => CleanupAsync(activityExecutionContexts));
+        context.Succeed(() => CancelAsync(activityExecutionContexts));
         return ValueTask.CompletedTask;
     }
 
-    private async Task CleanupAsync(IEnumerable<ActivityExecutionContext> activityExecutionContexts)
+    private async Task CancelAsync(IEnumerable<ActivityExecutionContext> activityExecutionContexts)
     {
-        foreach (var activityExecutionContext in activityExecutionContexts) 
-            await CleanupAsync(activityExecutionContext);
-    }
-    
-    private async Task CleanupAsync(ActivityExecutionContext activityExecutionContext)
-    {
-        await RemoveBookmarksAsync(activityExecutionContext);
-        await SaveActivityExecutionRecordAsync(activityExecutionContext);
+        foreach (var activityExecutionContext in activityExecutionContexts)
+            await CancelAsync(activityExecutionContext);
     }
 
-    private async Task RemoveBookmarksAsync(ActivityExecutionContext activityExecutionContext)
+    private async Task CancelAsync(ActivityExecutionContext activityExecutionContext)
     {
-        var filter = new BookmarkFilter { ActivityInstanceId = activityExecutionContext.Id };
-        await _bookmarkManager.DeleteManyAsync(filter, activityExecutionContext.CancellationToken);
-    }
-
-    private async Task SaveActivityExecutionRecordAsync(ActivityExecutionContext activityExecutionContext)
-    {
-        var activityExecutionRecord = _activityExecutionMapper.Map(activityExecutionContext);
-        await _activityExecutionManager.SaveAsync(activityExecutionRecord, CancellationToken.None);
+        await activityExecutionContext.CancelActivityAsync();
     }
 
     private static IEnumerable<ActivityExecutionContext> GetActivityExecutionContexts(AlterationContext context, CancelActivity alteration)
diff --git a/src/modules/Elsa.Alterations/Middleware/Workflows/RunAlterationsMiddleware.cs b/src/modules/Elsa.Alterations/Middleware/Workflows/RunAlterationsMiddleware.cs
new file mode 100644
index 000000000..140c598fb
--- /dev/null
+++ b/src/modules/Elsa.Alterations/Middleware/Workflows/RunAlterationsMiddleware.cs
@@ -0,0 +1,54 @@
+using Elsa.Alterations.Core.Contexts;
+using Elsa.Alterations.Core.Contracts;
+using Elsa.Alterations.Core.Models;
+using Elsa.Extensions;
+using Elsa.Workflows;
+using Elsa.Workflows.Pipelines.WorkflowExecution;
+
+namespace Elsa.Alterations.Middleware.Workflows;
+
+/// <summary>
+/// Middleware that runs alterations.
+/// </summary>
+internal class RunAlterationsMiddleware(WorkflowMiddlewareDelegate next, IEnumerable<IAlterationHandler> handlers) : WorkflowExecutionMiddleware(next)
+{
+    public static readonly object AlterationsPropertyKey = new();
+    public static readonly object AlterationsLogPropertyKey = new();
+
+    public override async ValueTask InvokeAsync(WorkflowExecutionContext context)
+    {
+        var alterations = (IEnumerable<IAlteration>)(context.TransientProperties.GetValue(AlterationsPropertyKey) ?? throw new InvalidOperationException("No alterations found in the transient properties."));
+        var log = (AlterationLog)(context.TransientProperties.GetValue(AlterationsLogPropertyKey) ?? throw new InvalidOperationException("No alteration log found in the transient properties."));
+        await RunAsync(context, alterations, log, context.CancellationTokens.ApplicationCancellationToken);
+    }
+
+    private async Task RunAsync(WorkflowExecutionContext workflowExecutionContext, IEnumerable<IAlteration> alterations, AlterationLog log, CancellationToken cancellationToken = default)
+    {
+        var commitActions = new List<Func<Task>>();
+
+        foreach (var alteration in alterations)
+        {
+            // Find handlers.
+            var supportedHandlers = handlers.Where(x => x.CanHandle(alteration)).ToList();
+
+            foreach (var handler in supportedHandlers)
+            {
+                // Execute handler.
+                var alterationContext = new AlterationContext(alteration, workflowExecutionContext, log, cancellationToken);
+                await handler.HandleAsync(alterationContext);
+
+                // If the handler has failed, exit.
+                if (alterationContext.HasFailed)
+                    return;
+
+                // Collect the commit handler, if any.
+                if (alterationContext.CommitAction != null)
+                    commitActions.Add(alterationContext.CommitAction);
+            }
+        }
+
+        // Execute commit handlers.
+        foreach (var commitAction in commitActions)
+            await commitAction();
+    }
+}
\ No newline at end of file
diff --git a/src/modules/Elsa.Alterations/Services/DefaultAlterationRunner.cs b/src/modules/Elsa.Alterations/Services/DefaultAlterationRunner.cs
index 5cf2df277..dfddcd7fa 100644
--- a/src/modules/Elsa.Alterations/Services/DefaultAlterationRunner.cs
+++ b/src/modules/Elsa.Alterations/Services/DefaultAlterationRunner.cs
@@ -2,10 +2,13 @@ using Elsa.Alterations.Core.Contexts;
 using Elsa.Alterations.Core.Contracts;
 using Elsa.Alterations.Core.Models;
 using Elsa.Alterations.Core.Results;
+using Elsa.Alterations.Middleware.Workflows;
 using Elsa.Common.Contracts;
+using Elsa.Extensions;
 using Elsa.Workflows;
 using Elsa.Workflows.Contracts;
 using Elsa.Workflows.Management.Contracts;
+using Elsa.Workflows.Pipelines.WorkflowExecution;
 using Elsa.Workflows.Runtime.Contracts;
 using Microsoft.Extensions.Logging;
 
@@ -14,8 +17,8 @@ namespace Elsa.Alterations.Services;
 /// <inheritdoc />
 public class DefaultAlterationRunner : IAlterationRunner
 {
-    private readonly IEnumerable<IAlterationHandler> _handlers;
     private readonly IWorkflowRuntime _workflowRuntime;
+    private readonly IWorkflowExecutionPipeline _workflowExecutionPipeline;
     private readonly IWorkflowDefinitionService _workflowDefinitionService;
     private readonly IWorkflowStateExtractor _workflowStateExtractor;
     private readonly ISystemClock _systemClock;
@@ -25,15 +28,15 @@ public class DefaultAlterationRunner : IAlterationRunner
     /// Initializes a new instance of the <see cref="DefaultAlterationRunner"/> class.
     /// </summary>
     public DefaultAlterationRunner(
-        IEnumerable<IAlterationHandler> handlers,
         IWorkflowRuntime workflowRuntime,
+        IWorkflowExecutionPipeline workflowExecutionPipeline,
         IWorkflowDefinitionService workflowDefinitionService,
         IWorkflowStateExtractor workflowStateExtractor,
         ISystemClock systemClock,
         IServiceProvider serviceProvider)
     {
-        _handlers = handlers;
         _workflowRuntime = workflowRuntime;
+        _workflowExecutionPipeline = workflowExecutionPipeline;
         _workflowDefinitionService = workflowDefinitionService;
         _workflowStateExtractor = workflowStateExtractor;
         _systemClock = systemClock;
@@ -86,15 +89,23 @@ public class DefaultAlterationRunner : IAlterationRunner
 
         // Create workflow execution context.
         var workflowExecutionContext = await WorkflowExecutionContext.CreateAsync(_serviceProvider, workflow, workflowState, cancellationTokens: cancellationToken);
+        workflowExecutionContext.TransientProperties.Add(RunAlterationsMiddleware.AlterationsPropertyKey, alterations);
+        workflowExecutionContext.TransientProperties.Add(RunAlterationsMiddleware.AlterationsLogPropertyKey, log);
 
-        // Execute alterations.
-        var success = await RunAsync(workflowExecutionContext, alterations, log, cancellationToken);
-        
-        // If the alterations have failed, exit.
-        if (!success)
-            return result;
+        // Build a new workflow execution pipeline.
+        var pipelineBuilder = new WorkflowExecutionPipelineBuilder(_serviceProvider);
+        _workflowExecutionPipeline.ConfigurePipelineBuilder(pipelineBuilder);
 
-        // Update workflow state.
+        // Replace the terminal DefaultActivitySchedulerMiddleware with the RunAlterationsMiddleware terminal.
+        pipelineBuilder.ReplaceTerminal<RunAlterationsMiddleware>();
+
+        // Build modified pipeline.
+        var pipeline = pipelineBuilder.Build();
+
+        // Execute the pipeline.
+        await pipeline(workflowExecutionContext);
+
+        // Extract workflow state.
         workflowState = _workflowStateExtractor.Extract(workflowExecutionContext);
 
         // Apply updated workflow state.
@@ -105,36 +116,4 @@ public class DefaultAlterationRunner : IAlterationRunner
 
         return result;
     }
-
-    private async Task<bool> RunAsync(WorkflowExecutionContext workflowExecutionContext, IEnumerable<IAlteration> alterations, AlterationLog log, CancellationToken cancellationToken = default)
-    {
-        var commitActions = new List<Func<Task>>();
-
-        foreach (var alteration in alterations)
-        {
-            // Find handlers.
-            var handlers = _handlers.Where(x => x.CanHandle(alteration)).ToList();
-
-            foreach (var handler in handlers)
-            {
-                // Execute handler.
-                var alterationContext = new AlterationContext(alteration, workflowExecutionContext, log, cancellationToken);
-                await handler.HandleAsync(alterationContext);
-
-                // If the handler has failed, exit.
-                if (alterationContext.HasFailed)
-                    return false;
-
-                // Collect the commit handler, if any.
-                if (alterationContext.CommitAction != null)
-                    commitActions.Add(alterationContext.CommitAction);
-            }
-        }
-
-        // Execute commit handlers.
-        foreach (var commitAction in commitActions)
-            await commitAction();
-        
-        return true;
-    }
 }
\ No newline at end of file
diff --git a/src/modules/Elsa.Workflows.Core/Contracts/IWorkflowExecutionPipeline.cs b/src/modules/Elsa.Workflows.Core/Contracts/IWorkflowExecutionPipeline.cs
index eea9b5f8f..4bf7429f4 100644
--- a/src/modules/Elsa.Workflows.Core/Contracts/IWorkflowExecutionPipeline.cs
+++ b/src/modules/Elsa.Workflows.Core/Contracts/IWorkflowExecutionPipeline.cs
@@ -2,9 +2,30 @@ using Elsa.Workflows.Pipelines.WorkflowExecution;
 
 namespace Elsa.Workflows.Contracts;
 
+/// <summary>
+/// Represents a workflow execution pipeline.
+/// </summary>
 public interface IWorkflowExecutionPipeline
 {
+    /// <summary>
+    /// The pipeline builder factory.
+    /// </summary>
+    Action<IWorkflowExecutionPipelineBuilder> ConfigurePipelineBuilder { get; }
+    
+    /// <summary>
+    /// Sets up the pipeline using the specified pipeline builder factory.
+    /// </summary>
     WorkflowMiddlewareDelegate Setup(Action<IWorkflowExecutionPipelineBuilder> setup);
+    
+    /// <summary>
+    /// The constructed pipeline delegate.
+    /// </summary>
     WorkflowMiddlewareDelegate Pipeline { get; }
+    
+    /// <summary>
+    /// Executes the pipeline with the specified workflow execution context.
+    /// </summary>
+    /// <param name="context"></param>
+    /// <returns></returns>
     Task ExecuteAsync(WorkflowExecutionContext context);
 }
\ No newline at end of file
diff --git a/src/modules/Elsa.Workflows.Core/Contracts/IWorkflowExecutionPipelineBuilder.cs b/src/modules/Elsa.Workflows.Core/Contracts/IWorkflowExecutionPipelineBuilder.cs
index 1a895b4d5..a2f37c9b0 100644
--- a/src/modules/Elsa.Workflows.Core/Contracts/IWorkflowExecutionPipelineBuilder.cs
+++ b/src/modules/Elsa.Workflows.Core/Contracts/IWorkflowExecutionPipelineBuilder.cs
@@ -12,6 +12,11 @@ public interface IWorkflowExecutionPipelineBuilder
     /// </summary>
     public IDictionary<object, object?> Properties { get; }
     
+    /// <summary>
+    /// The middleware components that have been installed.
+    /// </summary>
+    public IEnumerable<Func<WorkflowMiddlewareDelegate, WorkflowMiddlewareDelegate>> Components { get; }
+    
     /// <summary>
     /// The current service provider to resolve services from.
     /// </summary>
@@ -31,4 +36,12 @@ public interface IWorkflowExecutionPipelineBuilder
     /// Clears the current pipeline.
     /// </summary>
     IWorkflowExecutionPipelineBuilder Reset();
+
+    /// <summary>
+    /// Replaces the middleware component at the specified index with the specified delegate.
+    /// </summary>
+    /// <param name="index">The index of the middleware component to replace.</param>
+    /// <param name="middleware">The delegate to use as the new middleware component.</param>
+    /// <returns>A new instance of <see cref="IWorkflowExecutionPipelineBuilder"/> with the middleware component replaced.</returns>
+    IWorkflowExecutionPipelineBuilder Replace(int index, Func<WorkflowMiddlewareDelegate, WorkflowMiddlewareDelegate> middleware);
 }
\ No newline at end of file
diff --git a/src/modules/Elsa.Workflows.Core/Pipelines/WorkflowExecution/WorkflowExecutionMiddlewareExtensions.cs b/src/modules/Elsa.Workflows.Core/Pipelines/WorkflowExecution/WorkflowExecutionMiddlewareExtensions.cs
index f220f8c46..4e7221c11 100644
--- a/src/modules/Elsa.Workflows.Core/Pipelines/WorkflowExecution/WorkflowExecutionMiddlewareExtensions.cs
+++ b/src/modules/Elsa.Workflows.Core/Pipelines/WorkflowExecution/WorkflowExecutionMiddlewareExtensions.cs
@@ -1,3 +1,4 @@
+using System.Diagnostics.CodeAnalysis;
 using Elsa.Workflows.Contracts;
 using Microsoft.Extensions.DependencyInjection;
 
@@ -11,16 +12,50 @@ public static class WorkflowExecutionMiddlewareExtensions
     /// <summary>
     /// Installs the specified middleware component into the pipeline being built.
     /// </summary>
-    public static IWorkflowExecutionPipelineBuilder UseMiddleware<TMiddleware>(this IWorkflowExecutionPipelineBuilder pipelineBuilder, params object[] args) where TMiddleware: IWorkflowExecutionMiddleware
+    public static IWorkflowExecutionPipelineBuilder UseMiddleware<[DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicConstructors)] TMiddleware>(
+        this IWorkflowExecutionPipelineBuilder pipelineBuilder, params object[] args) where TMiddleware : IWorkflowExecutionMiddleware
+    {
+        var delegateFactory = CreateMiddlewareDelegateFactory<TMiddleware>(pipelineBuilder, args);
+        return pipelineBuilder.Use(delegateFactory);
+    }
+
+    /// <summary>
+    /// Replaces the terminal middleware component with the specified middleware component.
+    /// </summary>
+    public static IWorkflowExecutionPipelineBuilder ReplaceTerminal<[DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicConstructors)] TMiddleware>(
+        this IWorkflowExecutionPipelineBuilder pipelineBuilder, params object[] args) where TMiddleware : IWorkflowExecutionMiddleware
+    {
+        var index = pipelineBuilder.Components.Count() - 1;
+        return pipelineBuilder.Replace<TMiddleware>(index, args);
+    }
+
+    /// <summary>
+    /// Replaces the middleware component at the specified index with the specified middleware component.
+    /// </summary>
+    public static IWorkflowExecutionPipelineBuilder Replace<[DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicConstructors)] TMiddleware>(
+        this IWorkflowExecutionPipelineBuilder pipelineBuilder, int index, params object[] args) where TMiddleware : IWorkflowExecutionMiddleware
+    {
+        var delegateFactory = CreateMiddlewareDelegateFactory<TMiddleware>(pipelineBuilder, args);
+        return pipelineBuilder.Replace(index, delegateFactory);
+    }
+
+    /// <summary>
+    /// Creates a middleware delegate for the specified middleware component.
+    /// </summary>
+    public static Func<WorkflowMiddlewareDelegate, WorkflowMiddlewareDelegate> CreateMiddlewareDelegateFactory<[DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicConstructors)] TMiddleware>(
+        this IWorkflowExecutionPipelineBuilder pipelineBuilder, params object[] args) where TMiddleware : IWorkflowExecutionMiddleware
     {
         var middleware = typeof(TMiddleware);
 
-        return pipelineBuilder.Use(next =>
+        return next =>
         {
             var invokeMethod = MiddlewareHelpers.GetInvokeMethod(middleware);
-            var ctorParams = new[] { next }.Concat(args).Select(x => x).ToArray();
+            var ctorParams = new[]
+            {
+                next
+            }.Concat(args).Select(x => x).ToArray();
             var instance = ActivatorUtilities.CreateInstance(pipelineBuilder.ServiceProvider, middleware, ctorParams);
             return (WorkflowMiddlewareDelegate)invokeMethod.CreateDelegate(typeof(WorkflowMiddlewareDelegate), instance);
-        });
+        };
     }
 }
\ No newline at end of file
diff --git a/src/modules/Elsa.Workflows.Core/Pipelines/WorkflowExecution/WorkflowExecutionPipeline.cs b/src/modules/Elsa.Workflows.Core/Pipelines/WorkflowExecution/WorkflowExecutionPipeline.cs
index 9b1023dd6..a53439dcd 100644
--- a/src/modules/Elsa.Workflows.Core/Pipelines/WorkflowExecution/WorkflowExecutionPipeline.cs
+++ b/src/modules/Elsa.Workflows.Core/Pipelines/WorkflowExecution/WorkflowExecutionPipeline.cs
@@ -10,17 +10,21 @@ public class WorkflowExecutionPipeline : IWorkflowExecutionPipeline
     private WorkflowMiddlewareDelegate? _pipeline;
 
     /// <summary>
-    /// Constructor.
+    /// Initializes a new instance of the <see cref="WorkflowExecutionPipeline"/> class.
     /// </summary>
-    public WorkflowExecutionPipeline(IServiceProvider serviceProvider, Action<IWorkflowExecutionPipelineBuilder> pipelineBuilder)
+    public WorkflowExecutionPipeline(IServiceProvider serviceProvider, Action<IWorkflowExecutionPipelineBuilder> configurePipelineBuilder)
     {
         _serviceProvider = serviceProvider;
-        Setup(pipelineBuilder);
+        ConfigurePipelineBuilder = configurePipelineBuilder;
+        Setup(configurePipelineBuilder);
     }
-
+    
     /// <inheritdoc />
     public WorkflowMiddlewareDelegate Pipeline => _pipeline ??= CreateDefaultPipeline();
 
+    /// <inheritdoc />
+    public Action<IWorkflowExecutionPipelineBuilder> ConfigurePipelineBuilder { get; }
+
     /// <inheritdoc />
     public WorkflowMiddlewareDelegate Setup(Action<IWorkflowExecutionPipelineBuilder> setup)
     {
diff --git a/src/modules/Elsa.Workflows.Core/Pipelines/WorkflowExecution/WorkflowExecutionPipelineBuilder.cs b/src/modules/Elsa.Workflows.Core/Pipelines/WorkflowExecution/WorkflowExecutionPipelineBuilder.cs
index 3e46b827f..c61c6c4e5 100644
--- a/src/modules/Elsa.Workflows.Core/Pipelines/WorkflowExecution/WorkflowExecutionPipelineBuilder.cs
+++ b/src/modules/Elsa.Workflows.Core/Pipelines/WorkflowExecution/WorkflowExecutionPipelineBuilder.cs
@@ -19,6 +19,9 @@ public class WorkflowExecutionPipelineBuilder : IWorkflowExecutionPipelineBuilde
     /// <inheritdoc />
     public IDictionary<object, object?> Properties { get; } = new Dictionary<object, object?>();
 
+    /// <inheritdoc />
+    public IEnumerable<Func<WorkflowMiddlewareDelegate, WorkflowMiddlewareDelegate>> Components => _components.ToList();
+
     /// <inheritdoc />
     public IServiceProvider ServiceProvider
     {
@@ -51,6 +54,12 @@ public class WorkflowExecutionPipelineBuilder : IWorkflowExecutionPipelineBuilde
         return this;
     }
 
+    public IWorkflowExecutionPipelineBuilder Replace(int index, Func<WorkflowMiddlewareDelegate, WorkflowMiddlewareDelegate> middleware)
+    {
+        _components[index] = middleware;
+        return this;
+    }
+
     private T? GetProperty<T>(string key) => Properties.TryGetValue(key, out var value) ? (T?)value : default(T);
     private void SetProperty<T>(string key, T value) => Properties[key] = value;
 }
\ No newline at end of file