diff --git a/specification/eventgrid/Azure.Messaging.EventGrid/main.tsp b/specification/eventgrid/Azure.Messaging.EventGrid/main.tsp
index 173d0a67fa53..e1a828eb56e5 100644
--- a/specification/eventgrid/Azure.Messaging.EventGrid/main.tsp
+++ b/specification/eventgrid/Azure.Messaging.EventGrid/main.tsp
@@ -231,6 +231,6 @@ namespace Azure.Messaging.EventGrid {
 
     @doc("Array of LockTokens for the corresponding received Cloud Events to be acknowledged.")
     @body    
-    tokens : LockToken[];
+    tokens : LockTokenInput;
   }, LockTokensResponse >;
 }