My current fone, Droid 4 on unlimited, is basically becoming a paper weight day in and day out. I'm planning to use my friend's HtC rezound as I will open the droid 4 and see if I can fix the problems on the fone. If I do this, my unlimited should still be intact right? And if I do fix my droid 4, can I just switch back to it from the rezound immediately and still have my unlimited? Also, where will I activate it? Online or at store? Will they be free of charge as well? Thanks!