I have a family plan on AT&T with 3 lines. Two are iPhones that I've already preordered/upgraded and will be keeping. The third line is a regular phone that costs something like $10/month. I'd like to "upgrade" this line and gift the phone. Since I won't be canceling the voice line or number, I shouldn't have to pay a termination fee, right? I'll just have to buy a data plan for the iPhone upon purchase and cancel it whenever I want to. Will I have to purchase a more expensive voice plan, and can that be reverted back to the $10 plan without penalty? Is this correct?