My plan is to trade in my wife's 5c (only has about $40 to pay off with trade) and use that upgrade for a 6s Plus, and give her my current 6 Plus. How does the physical trade work? I read their FAQ and it talks about sending it via mail, etc. Do I have to have the phone on me when I purchase? I would think so but how would that affect ordering it online? Do I have a window/time frame to turn it in? Its much easier to check AT&T since I work close to a store then to drag her around with her phone to check if they have stock. What about using Next at another store like Best Buy or Target, do you give them the old phone? Thanks.