This function causes the user who created or found the specified session to leave it. You can get the session ID pointer from the async_load DS map that is returned in the Asynchronous Social Event when you created or found a session (see xboxlive_matchmaking_create() for more details).
Argument Description session_id The Session ID pointer of the session to leave.
if gamepad_button_check_pressed(0, gp_start)
The above code checks for a gamepad button press and if one is detected then the user will logged out of the given matchmaking session.