diff --git a/src/core/Elsa.Abstractions/Repositories/IWorkflowInstanceRepository.cs b/src/core/Elsa.Abstractions/Repositories/IWorkflowInstanceRepository.cs
index 785264c85..704b73696 100644
--- a/src/core/Elsa.Abstractions/Repositories/IWorkflowInstanceRepository.cs
+++ b/src/core/Elsa.Abstractions/Repositories/IWorkflowInstanceRepository.cs
@@ -11,23 +11,14 @@ namespace Elsa.Repositories
     {
         Task SaveAsync(WorkflowInstance workflowInstance, CancellationToken cancellationToken = default);
         Task DeleteAsync(WorkflowInstance workflowInstance, CancellationToken cancellationToken = default);
-
         Task<bool> IsWorkflowIsAlreadyExecutingAsync(string? tenantId, string workflowDefinitionId, CancellationToken cancellationToken = default);
-
-        Task<WorkflowInstance> GetByIdAsync(string workflowInstanceId, CancellationToken cancellationToken = default);
-
+        Task<WorkflowInstance?> GetByIdAsync(string workflowInstanceId, CancellationToken cancellationToken = default);
         Task<IEnumerable<WorkflowInstance>> ListAsync(int page, int pageSize, CancellationToken cancellationToken = default);
-
         Task<IEnumerable<WorkflowInstance>> ListByBlockingActivityTypeAsync(string activityType, CancellationToken cancellationToken = default);
-
         Task<IEnumerable<WorkflowInstance>> ListByDefinitionAndStatusAsync(string workflowDefinitionId, string? tenantId, WorkflowStatus workflowStatus, CancellationToken cancellationToken = default);
-
         Task<IEnumerable<WorkflowInstance>> ListByStatusAsync(WorkflowStatus workflowStatus, CancellationToken cancellationToken = default);
-
         Task<IEnumerable<WorkflowInstance>> ListByDefinitionAsync(string workflowDefinitionId,string? tenantId,CancellationToken cancellationToken = default);
-
         Task<WorkflowInstance?> GetByCorrelationIdAsync(string correlationId, WorkflowStatus status,CancellationToken cancellationToken = default);
-
         Task<IEnumerable<WorkflowInstance>> ListByCorrelationIdAsync(string correlationId,WorkflowStatus status,CancellationToken cancellationToken = default);
         Task<int> CountAsync(CancellationToken cancellationToken = default);