post https://api.twilio.com/2010-04-01/Accounts//IncomingPhoneNumbers/.json
This endpoint is used to exchange phone numbers between an account and subaccounts.
WhatsApp Activated Numbers
If you have a WhatsApp Sender connected to your phone number, it will not be exchanged between subaccounts. To move phone numbers connected to WhatsApp Senders, open a support ticket to move the WhatsApp Sender before moving the phone number.
You can transfer numbers between subaccounts or between your main account and any one of your subaccounts. You must use your main account's credentials when making the API request to transfer a phone number.