Currently I'm a secondary line on a month to month AT&T family plan with an iPhone 3G. The account holder is my stepfather and the only other line we'll be moving to Verizon. My question is can I go ahead and sign up for our new plan and get his phone (Samsung Convoy) and port our numbers? I figured I could just get any phone then swap it for the X on the 15th. Is that possible? If not I'll probably just open a new account online as early as I can on the 15th and overnight the phones.