Hi,
Per our research a status of Message Recall actions can be found within MessageTraceDetail logs. As you probably noticed Message Trace logs simple show "Failed" status of "Recall:" messages, but MessageTraceDetail logs provide more details:
In case of failed recall (in our tenant we deny to recall already read emails):
"Detail : Reason: [Stage: OnPromotedEvent][Agent: Transport Message Recall Agent];Message recall process complete, dropping the recall email. Result:MessageAlreadyRead"
and in case of success recall:
"Detail : Reason: [Stage: OnPromotedEvent][Agent: Transport Message Recall Agent];Message recall process complete, dropping the recall email. Result:Success"