How to change or delete your Mobile number on Twitter
January 27, 2012 – 10:50 am1. Log in to your Twitter Account
2. Click on Settings
3. Click on Mobile Tab
4. Click on Delete my phone link (under/below Save button)
5. After deleting your Mobile number, you can add/change your new Mobile number.
6. Soon after changing your mobile number, type GO on your mobile and send it to 53000.