So we decided to pay for my mothers phone service and add her to our family plan. Decided to get her an iPhone and have a couple questions. 1. Instead of getting a "free" iPhone4, I figured I'd give her my 4S and get a new 5 for me. If so, is it as simple as just moving the SIM card from my phone to the other? 2. Can she keep her number or does she need to get new number? She currently has ATT and is not under contract. I know that you can port a number when moving service but wasn't sure if you could do it within the same company. 3. Anything else I need to know? Thanks in advance for any advice or input!