I reserved a black Verizon iPhone 7 Plus at Apple because I read that the Verizon version of the iPhone 7 can be bought unlocked. I am an AT&T customer so not sure how I would activate it. Questions: Has anyone had success doing this? Will Apple help me get it set up when I pick it up? Can I just put in my existing SIM card before it boots up to activate? Or what is the correct procedure? They were out of AT&T versions and I just want to buy it in full tomorrow when I pick it up. Thanks!