diff --git a/temporal/workflow.py b/temporal/workflow.py
index 5728597..65437f6 100644
--- a/temporal/workflow.py
+++ b/temporal/workflow.py
@@ -88,9 +88,9 @@ class SimulationWorkflow:
         )
         
         if sim_data.get("CallbackWorkflowId"):
-            client = await Client.connect(TEMPORAL_URL)
-            handle = client.get_workflow_handle(sim_data["CallbackWorkflowId"])
-
+            handle = workflow.get_external_workflow_handle(
+                sim_data["CallbackWorkflowId"]
+            )
             await handle.signal("notify_done")