How to change the defult phone number in iMessage

i changed my number but imsg & facetime still reconized the old one, i did the below troubleshooting but it didn’t work:

1. Go to Settings > Messages>Turn off iMessage.
2. Go to General > Reset > Reset Network Settings.
3. Once the iPhone is open.
4. Go to Settings > Messages>Turn ON iMessage.
5. This will recognize the new sim and have it verified.

I need help plzzzz