I'm considering upgrading my daughter's phone through wirefly and getting her an Evo, but I have some questions. I only want to upgrade her phone and I can't figure out how to. I'm on a sprint 1500 minute share plan with unlimited text/data. I currently have 2 primary lines and 2 additional lines on the family plan. My daughter is on of the additional lines. I'd like to only upgrade her phone. Can you guys help me out?