I want to change my cellphone provider to Page Plus Cellular. I have a Amp'd Phone Number but I just bought a used Verizon phone that I want to use on Page Plus service. What do I need to do in order to transfer? Also, under what circumstances would I need an ESN number change? (This may be totally unrelated it just keeps popping up and I am wondering what it is.) I called Verizon to check on the ESN of the used phone and they said it wasn't registered. Will I still need to change it?