Hello! I have an ATT iPhone 7. I have wanted to be able to do this for a few years but this issue between the modems I decided now might be a good time to try. I live in Florida but work for 2 months every summer in northern Wisconsin. In Florida ATT is a better signal, but in the north Verizon has much superior service. Not sure if the wooded area makes a difference. Anyway, I have the option for a few more days to return my phone to Apple. I am on the iPhone Upgrade Program, and I am off contract with ATT by several years now. I would want to return my ATT phone, pick up the same model with Verizon capability, activate the phone on Verizon then cancel it immediately after finishing the transaction. Put the ATT sim card into the new Verizon-capable model and leave things alone. In May when I get up north I would use their service for a couple months, get a small voice/data Verizon plan (as we would still be paying for my service with ATT, but at least I'd be able to use the service I'm paying for) then in August go back to Florida and ATT. Anyone have any input or experience doing anything like this, or at least getting a Verizon phone to use on ATT? I know I can get a Sim-free phone but the Apple upgrade program doesn't work with Sim free phones and I am like the target market for that program.... annual upgrade like clockwork, and always use AppleCare at least once a year. Thanks in advance for any input anyone can share.