How To Remove Your Old Account - Microsoft Authenticator
1. Open the Microsoft Authenticator App
Locate and tap the Microsoft Authenticator app icon on your mobile device to launch it.
2. Access the Account List
Upon opening the app, you'll see a list of accounts you've added.
3. Select the Account to Remove
Identify the account you wish to remove and click on it.
4. Open Account Options
Tap the Cog Icon located at the top-right corner of the account tile to access more options.

5. Remove the Account
From the dropdown menu, select "Remove account".

6. Confirm Removal
A confirmation prompt will appear asking if you're sure you want to remove the account 'from your device' or 'this app only' Click this app only - if you don't see this prompt, you should just need to tap "Remove" to confirm.