How to access private attribute of a class from its Friend Class

Hi Experts ,

I am coding in Method (DO_SAVE) of class /BOBF/CL_TRA_TRANSACTION_MGR.

I need to access private variable ( MO_BOPF) of class /BOBF/CL_TRA_SERVICE_MGR ( Friend of /BOBF/CL_TRA_TRANSACTION_MGR ).

Please help me to understand how can i access private attribute of one class from its friend class.

Regards- Abhishek