I upgraded one of our lines on apple.com via pre-order. Our carrier is AT&T. Turns out our order was not going to get delivered until 9/28. Instead of waiting I went to the apple store and bought a phone by upgrading one of my other lines, and then swapping the phone numbers. Now the phone that I pre-ordered has come in and I want to sell it sealed in the box. How does the buyer activate? Is this phone pre-activated on my number? Is this going to mess my service up? Thanks in advance for the help.