If the reply Message has a signature, then wildcard arguments are provided for all return, out and inout ownedParameters of the signature Operation. Source Unified Modeling Language 2.5.1
If the identity of a reply Message is obvious (e.g., when its sendEvent is the only reply within the extent of an ExecutionOccurence where there is only one receipt of an Operation call message), the label may be omitted to simplify the diagram. Source Unified Modeling Language 2.5.1
