Bought a 16GB 5s from store.apple.com in mid November. I thought 16GB would be enough as I had a 16GB iPhone 5. Well I've been messing around with the slo mo stuff and seem to be taking more photos with it. I need 32GB. This phone was purchased for ATT upgrade ($199). Will I be able to return it and get a 32GB version ($299) and still get the upgrade price? The other thing is that I'd like to keep the current phone until the other one arrives. Any ideas? Do I need to talk to ATT first?