Sorry, I know this has probably been asked and answered but I could not find anything in a quick search. I have 2 lines on a family plan; my line was upgraded almost 1 year ago so is not eligible, but my wife's line is contract free and fully eligible. Can I upgrade my wife's line to an iPhone (yes I have her permission that she wants to keep her old "dumb" phone) and then activate it on my line? The only thing tying it to a line is the SIM card correct? What would be the procedure?