Hey Faiz,
Since you dint mention tat whether you use Module pool approach or simple selection screen here is the solution for both,
If simple selection screen, Handle the scenario in your PF-STATUS by giving leave list processing or LEAVETOSCREEN0.
OR
If it is simple Module pool follow,
MODULE user_command_9000 INPUT.
CASE sy-ucomm.
WHEN 'BACK'.
LEAVE TO SCREEN 0.
ENDCASE.
ENDMODULE.
Happy Coding,
Santhosh Yadav