I think it works like this; people buy a SIM card from the same carrier, and call that carrier and ask them to move the victim's phone number to that SIM card.

I think it works like this; people buy a SIM card from the same carrier, and call that carrier and ask them to move the victim's phone number to that SIM card. I know T-Mobile in the US allows you to buy a SIM card in any of their stores. I am sure other US carriers have the same offer.