How do I reset MFA for someone who lost their phone?

While enforcement is on, MFA can't be switched off for anyone, so the reset takes a few steps:

1. Turn enforcement off (Settings → Data & Security → Multi-Factor Authentication).
2. Open the person's agent or contact edit screen, switch Multifactor authentication off and save.
3. Turn enforcement back on.

The next time that person signs in, they're asked to set up MFA again with their new device. Note that turning enforcement back on also signs out anyone else who hasn't configured MFA yet.