If the triggers of an AcceptEventAction are all for ChangeEvents and/or CallEvents, then the AcceptEventAction has no result OutputPins (unless the AcceptEventAction is an AcceptCallAction ...) Source Unified Modeling Language 2.5.1
NOTE. Operation referenced in the CallEvent of an AcceptCallAction should not have an associated method Behavior. Otherwise, a call to the Operation will have the immediate effect of executing the method and will not be placed into the event pool ... Source Unified Modeling Language 2.5.1
