Question. I'm on AT&T family share plan. I currently have an iPhone 4 which is eligible for upgrade at any time. I plan to add a family member line to my acct. I was going to start new iPhone 4spurchase for addl line. Then I was going to use the 4s for me and give the iPhone 4 to family member. Now, my question, when iPhone 5 comes out later, how can I use my upgrade from iPhone 4 to get that? Do I and family switch our phones and sim cards so now it shows I'm ready for upgrade and family member I'll have my used iPhone 4s. Make sense? Wanted to know before I add this line. Thanks!