so i'm looking to trade in my iphone 4 for a 4s. i'm concerned with how the trade-in process works for things like gazelle or nextworth. so you get a quote... what's next? do you ship it to them and then wait for the money; so then i won't be having a phone for about a week? i'm considering that i'd rather go to a local Bestbuy or my carrier's store to trade it in (if what i said above is the case), but am i able to swap a 4 for a 4S in-store right away? my carrier is AT&T and i currently have a black 16GB.