I just signed up for a new Sprint family plan online. The phones arrived and I have activated them. In the next day or so I am going to port my existing numbers from AT&T. But one of the new Sprint lines came with a nice number and I was wondering if there was any way I could simultaneously or otherwise port this number out to a pre-paid or similar device so I could keep it as a backup/2nd line? Any way to do this? Thanks.