And how do you plan on going about it? I've read on here that you can simply call and have them swap numbers around on the SIM cards, but I've heard conflicting things from AT&T. Some at AT&T say I can just call, others say you have to bring both handsets in to perform this procedure. I've also been told by one rep that I actually have to activate the phone first on the main account that was eligible for the upgrade, then switch it. I'm more inclined to believe what I've read on here than AT&T, just curious what others here are planning on doing. My main concern is not de-activating the other line on the account that I am doing the upgrade swap with, if that happens it will be a real pain in the arse since I won't be able to call him to let him know.