SIM Card question//phone swaps without involving carrier
Ok, so I think I said before that my ip4 got stolen last weekend. My friend lent me her upgrade so I didn't shell out $700 on vacation. I was going to just return it and reverse everything when my ip4s showed up, but right now it's sounding more like it would be a lesser pain in the keester if I just send her this phone and not bother reversing it, since its on her account and I paid ATT for it.
If I just sent this back to her, she can pop her iP4 sim into it and right as rain, back on her number on her account and like it never happened and she just upgraded on her own? Then my new phone goes to my account, my number?