I am currently on the AT&T Next 12 Month Program with a iPhone 6 Plus. I am eligible to upgrade to the iPhone 6S Plus when it comes out next month. Can I do this on the Apple Website, does anyone know how I “turn in my phone to AT&T” which is required as part of the upgrade? I would like to buy the new one through Apple and turn my current one in through AT&T. Does anyone know if this is possible? I've gotten mixed answers on this and no one seems to know. Thanks.