You can view all the phone numbers purchased by you and your team in the Phones section of Settings. Here you can update the owner of a phone number and delete a phone number.

1. To update the owner of a phone number, hover over the phone number and click on the pencil icon.
2. In the Field to update, select owner
3. Choose the new owner from the dropdown list (Here you can select All Users that makes everyone the owner of that particular phone number)
4. Click on Update

To delete a phone number, hover over the phone number and click on the trash icon, then click on Yes, Delete. Your phone number would be deleted and no further charges would be levied related to this number. 

However, please note that once deleted, the same number may not be available in your future purchases.