Can I Transfer a Number from Another Provider to OWA?

Yes, it is possible to change between Solution Providers as long as the source and destination of the Facebook Business IDs are the same across accounts. The number used to set up WhatsApp for Business API can be ported between WhatsApp Business API accounts. This allows businesses to switch between solution providers or switch their numbers to a new account. You can get more information about phone number porting by following the link.