Will Airvoice ever change the phone number on an already active SIM? I have an active phone & SIM that I recently added a $100 refill to. I'd really like to port a new number to that phone.

I called Airvoice and was told it's not possible to change the number on an existing SIM, and that I would have to buy a new SIM to get a new number or a port in and they could not move the airtime to the new account. The CSA I spoke with did not seem to be altogether clear on what I was asking, so I thought I'd check here.