Each phone has a SIM card, which contains a lot of valuable information about users and operators. However, the most important is the subscription’s phone number. The scammer, by persuading the user to change the Sim card, gains access to the victim’s important data.

https://www.darkreading.com/theedge/sim-swapping-attacks-what-they-are-and-how-to-stop-them/b/d-id/1336662