ATT next - Switching phones? Question

hello! i have an iphone 5c that I got on the att next program (pay for the phone monthly for 18 or 24 months) im not a huge fan of iphone, so I have a friend also on ATT with an LG 2g, who wants to trade phones.

Can I do this? Im assuming since I technically dont "own" the phone I wouldnt be able to switch. We would have to get our phones activated at the ATT store (since going iphone to android) so I was just curious if anyone had a direct answer to this.

thanks!