Memo:
In BizTalk, if you want to route a message directly back to the initiator, promote the EpmRRCorrelationToken and the RouteDirectToTP.
The EpmRRCorrelationToken value can be read from the request message and promoted while the RouteDirectToTP property can be promoted according to your requirement.
A standard scenario is:
You have exposed a bi-direct service to the consumer, once you get the request you have to return a Sync response immediately. By this way, you can have a outbound mapping which inflect from the request, and the return message can be send to the initiator quickly.
You have to promote the below properties:
EpmRRCorrelationToken
RouteDirectToTP