I have a 3 line account, 2 smartphones with unlimited and one basic. All three are out of contract. I would like new smartphones but obviously want to keep unlimited. Is it still possible to use the basic phone line to process the upgrades, then drop that line back to a basic phone and activate the smartphone on the unlimited line? This process would involve doing this twice and a transfer of one upgrade since I want 2 new smartphones. Has anyone had success lately?