I have a 6+ that I purchased on launch day last year on the ATT Next plan and I want to upgrade to the 6s+ next week. I talked to a rep in store the other day and he says I owe 240.00 still in payments on the phone and I can pay that and I would be able to upgrade but I have to turn in my phone. My question is if I sell my phone (on eBay, icracked, etc.) and use the money I get from selling it there, am I able to buy my 6+ outright and not have to turn it in and still be able to upgrade? Also, I am on the ATT Next 18 month plan. Thanks in advanced for any insight.