So, my dad has an upgrade coming up on February 1st. He's using an iPhone 3GS but has no issue with it and doesn't want to upgrade. He told me that he might use his upgrade to get an iPhone 5 and give it to me. We're both on AT&T but I'm on a seperate plan with my mom. I'm using an iPhone 4S. What I need some advice or help with is, how can him and I get it so he can use his upgrade but keep his phone number and such on the sim card in his 3GS and how i can get a nano sim from AT&T with my number to put into the iPhone 5.