Talk:South Africa/@comment-70.94.108.195-20160530211402/@comment-103173-20160530215415

Nothing. As long as your current phone is SIM-unlocked, just take your existing SIM out, put it in a safe place, and put your new South African SIM in your phone. To your existing carrier, all you've done is turned your phone off. They have no indication that you're using your phone with a different SIM.