Can I change the WhatsApp number before Deployment?
Yes, you can change the number before the deployment.
If your WABA is created with embedded signup, you should be able to access the WhatsApp Manager.
Click the "Add Phone Number" on the top right corner to add the new number with the same display name, as WhatsApp will need to approve the new phone number as well.
Then, select the new number in the deployment when the display name is approved.
Please submit a ticket to contact Stella Support to change the number if you are not using the embedded signup.