So I thought I'd post here since both Apple and AT&T are unhelpful. I want to upgrade to an iPhone 4S. However my upgrade is in April. I'm part of a family plan though and she has an upgrade but doesn't want it, so I'm taking it. Now, if I just upgrade her to the iPhone 4S, can I myself swap the SIM cards? Or do I need AT&T/Apple to do it? Basically can I take her iPhone upgrade?