How to make the transition from WhatsApp App to WhatsApp Business API and vice versa?

Any phone number can be upgraded to WhatsApp Business API provided the number isn’t active on any of the WhatsApp Apps. So, if a number is registered on WhatsApp App and one needs to get the API on the same number, the WhatsApp Account must be deleted.

Note - If you don’t wish to use WhatsApp Business API, you can downgrade the number & restore it back to WhatsApp Apps.
​ Here is How you can Delete your Whatsapp Business App before Applying for the API:

  1. Open WhatsApp
  2. Tap More Options (three dots) > Settings > Account > Delete My Account
  3. Enter your phone number in full international format and tap DELETE MY ACCOUNT
  4. Select a reason for why you’re deleting your account in the dropdown
  5. Tap DELETE MY ACCOUNT