Could someone add a line to a family plan, then use that to buy an iPhone 4 and then cancel the other line? I'm not sure if this is possible, and Its not my plan. That is why I am asking. To make this clearer lets use an example. Someone has a plan that doesn't have an upgrade until 2013, but its on a family plan. Could this person take that line, cancel it, and open another to get an upgrade? Cost of this would be? I'm about 99% sure you wouldn't be able to keep the number. But is this possible? Thanks!