Log in to Azure portal -> Active Directory -> Users.
Add user phone under Authentication contact info. Click on “Require re-register multifactor authentication. Reset password. Send email to user to login here ;
User will be able to change the temp password. Next step will be the wizard that will re-register multifactor authentication on user phone in Microsoft Authentication App.
If you want to re-register for Azure multi-factor authentication and use Authentication app on a new/existing phone, follow these steps;
Login to Azure Portal -> Active Directory -> Your user account –> Profile
Click on Authentication methods link.
Click on Access Panel Profile link. This will take you to your profile page.
Click on Additional security verification link.
Select this option to view QR coce;
You are ready to restore your credentials.