Before you can connect a new phone to your Microsoft authenticator you must delete the old authenticator connection.
Please follow these steps:
1. On a computer, navigate to myaccount.microsoft.com and log in with your Blue Ridge credentials.
2. Click on update info in the Security Info box.
3. Look for an item listed as Microsoft Authenticator and that has your old phone listed next to it.
4. Click Delete.
5. You can now download the Microsoft authenticator app to your new phone and follow these instructions to finish setting it up.
https://blueridgecc.freshservice.com/support/solutions/articles/17000151568