Hello all, I was hoping you guys can help me get an answer... I currently have an iPhone 6 but would like the 6 plus, yes I'm aware of the the 6s but I don't want to mess with my contact so I will be able to get the iPhone 7 next summer. My question is if I buy an iPhone 6 Plus sim free from Apple would I be able to take the sim out of my iPhone 6 and put it in the 6 plus and have it work? Would AT&T make me pay more if they noticed I'm not using the iPhone 6? Thanks!