Hello
You can reset MFA for your users by following these steps:
Search for the User: Go to the user profile by searching for the user and clicking on the name from the list.
Authentication Methods: In the left pane of the user profile, click on "Authentication methods". This will open a top status bar with options.
Require Re-register MFA: Click on "Require re-register multifactor authentication". This should prompt the user to set up MFA again when they next log in.