You can easily move a DID assigned to a Service and Connection to either another Connection or Service.
Navigate: Number Inventory > Move DID
Move DID dialog with Account and Connection dropdowns before saving the transfer
Number Inventory page with the Move DID icon highlighted
When clicking on the "Move DID" icon for a specific DID, you will be able to select a Service that you would like to move the DID to. Once a Service is selected, it will display all active Connections within the service. For MS Teams and Hosted Voice, you will not be able to select a connection and the default active connection will be used. You can then select which connection you would like the DID to land on.
Once you hit the Save button, the change is completed and is active immediately.