SAP Message /SPE/CP106 - Inbound delivery &1 is already contained in an RFC queue

Diagnosis
A different process has tried to change the given inbound delivery andthis inbound delivery is still contained in an RFC queue.

System Response
The system does not allow to change this inbound delivery at the moment.The existing entry in the RFC queue must be processed first.

Procedure
Try to process this inbound delivery later.