You you call a function via RFC you need to provide the RFC DESTINATION for the remote system:

CALL FUNCTION ‘ZSNEEZED’
  DESTINATION ’sistema_longe_daqui’.

What if, for some reason, the function running in the remote system needs to call a function in the original system? How would you do it?

It’s simple. SAP helps you. There is a predefined RFC DESTINATION called BACK which represents the original caller system.

FUNCTION ZSNEEZED.
(…)
CALL FUNCTION ‘ZBLESSYOU’
  DESTINATION ‘BACK’.
(…)
ENDFUNCTION.

Automatical.

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