OK so I have two lines on a family line, mine and my wife's. My line is the additional line and is not due an upgrade for a while. My wife's line is the one I bought the iPhone 4 on, since she got a $299 32GB upgrade. Now, she doesn't want an iPhone 4, so she wants me to have it, so when it arrives can I just cut my sim down to size and put it in the iPhone and be done? Does that work ok? Thanks!