Should you lose access to your configured MFA options, you can update your MFA configuration through this reset procedure. At the Sign In screen there is a button to Reset MFA, which you can access without authentication. However, you will be required to confirm your e-mail first.
Once you have done so you need to validate this request using a Recovery Code or decrypting a message using your personal PGP key. The validation options should match your profile at this point: if you did not download your Recovery Codes or set your PGP key, those options will not be available. The fallback option is requesting FIRST support, which might rely on validating your ID through a secure channel.
After you validate the request, you will be redirected to your MFA Configuration page.