How to handle RFC Application Errors

I am make an RFC call to SAP to call a function module that for example should create or change a salesorder or a quote. A change salesorder in sap could fail for many different reasons one of which is "object locked". When such a call fails the BAPIRET2 structure is populated with TYPE = "E" messages. One solution is to ask the sender to resend, but this is not always the most efficient and convenient way. Could some of you share you ideas and experiences regarding this issue.

Thanks