To change your phone number within WhatsApp, follow these steps:
- Insert the new SIM card with the new number into your device.
- Open WhatsApp.
- Check if your old phone number is currently verified in WhatsApp by going to WhatsApp > Menu Button > Settings > Account > Payment info.
- Go to WhatsApp > Menu Button > Settings > Account > Change number.
- Enter your old phone number in the top box.
- Enter your new phone number in the bottom box.
- Tap Done at the top of the screen.
- You will be prompted to verify your new phone number.