How to reset Outlook to remove an account

In migrating my Xfinity email accounts to Yahoo mail, I foolishly tried Outlook rather than using Yahoo's web mail platform. I set up an account in Outlook using my Xfinity password. Then I successfully migrated that account to Yahoo, where it suggested I change my password, and I did. Now Outlook recognizes neither password, and I cannot get past the sign-in screen, so I can't get to any Outlook menus to remove the account.

Is there a way to reset Outlook to remove the account and the conflicting passwords? I tried uninstalling and reinstalling Outlook, but that changed nothing, the first screen that appears is the sign-in screen and I can't get past it.