I have iPhone 4, but not eligible for upgrade price, but another family is, and she has a dumb-phone. So buy iPhone 4S using her phone number, pick data plan, etc. at Apple Store. I believe at that point her dumb-phone will then NOT work as her SIM is de-activated. Bring iPhone 4S home, now what do I do? Is it as easy as switching SIM cards, and then calling AT&T to cancel data plan on her phone number? Switching SIM cards: Take my iPhone 4 micro SIM and put in iPhone 4S, I would then take the iPhone 4S micro SIM and put in her dumb-phone but dumb-phone takes only takes regular size SIM. Also, do I simply hook up the 4S to iTunes and select RESTORE from iPhone 4 Backup? Is that the best way, is there such thing as a "clean install" on iPhone? Thanks!