hi there,

As per  your query , you have to  change your number follow these steps to change you number with a new number :

1. On your Android device, open Settings Google.
2. At the top, tap Personal info.
3. In the "Contact info" section, tap Phone.
4. Select the phone number that you want to make changes to.
5. Next to your number, select Delete. .
6. At the top left, tap Back .
7. At the top, tap Security.

Hope you understand , In case of any issue revert here and also make a new query for the same.

Thank you :)