The method is:

1. Open and log in to the Douyin software on your mobile phone, and click the My button in the lower right corner.

2. In the interface that appears, click the three horizontal lines in the upper right corner to enter.

3. After the page jumps, pull down to the bottom and click the Settings button to enter.

4. In the Settings interface that appears, click the Feedback and Help button to enter.

5. After the page jumps, click How to change the original mobile phone number to enter.

6. Enter the unbinding interface of the cancelled mobile phone number, enter the original mobile phone number and click Next.

7. In the interface that appears, enter the new mobile phone number to be bound and click Next.

8. Enter the verification interface of the new mobile phone number, enter the verification code received on the mobile phone and click Next.

9. At this time, the interface pops up a prompt that the mobile phone number has been successfully bound, which means that the original bound mobile phone number has been unbound.