How To Unlink a Phone Number from WeChat
Wechat cannot unlink phone number
How can I create a WeChat account without using a phone number?
How to link your phone number to WeChat account？
What if I want to link a new phone number to WeChat? Use an email address or QQ and start from scratch again.
Read 1 and 2 above to find out why.
Then sign out and delete the app from your mobile device.