I'm going to buy a Droid phone from Amazon since it's cheaper, but I don't have an upgrade available so I am using my dad's instead. The problem is Amazon doesn't have the option to transfer upgrades. If I buy the droid using my dad's number, will I be able to call and activate my number instead when the phone arrives and not affect my dad's phone? Oh, and I'm having trouble deciding between the Droid X or Droid Incredible..any opinions? Thanks!