I have an iPhone 4 and an iPhone 4S. Both activated and on the same account. Can I swaop the Sim cards to swap the phone numbers associated with the devices and be done with it? I called AT&T and they want me to come down in oerson, and pay $18.00 per phone. From what I read a Sim swap does effectively the same thing. Nothing really changes on the account. Will this work? I don't want to brinck the sim and end up having to go to AT&T with dead phones.