I can't remember from years past how this worked. I ordered an AT&T iPhone 5 today from the Apple site (unfortunately with the 2 week ship date). We have a family plan with two lines. One is eligible for an upgrade and one is not, but we want to switch the phone from the eligible line to the non-eligible line. It's a little trickier than it used to be because the iPhone 5 uses a nano SIM rather than a micro SIM, so I'm guessing it's going to take a call to AT&T to sort out, but I'm hoping that the phone isn't already activated to the line we don't want.