Step-by-Step
1. Navigate to Administration > User Accounts, search for the user and click on their name.
2. Click on the Security tab, then under "Roles," fill in the "System User" checkbox.
3. Under "Permissions," only enable the "Appointments Administrator" permission.

Accidentally enabling the "Account Administrator" permission may give tutors powers that go beyond what was intended.
4. Finally, click the Save Changes button at the top-right of the screen.
If it worked, then tutors with this permission now have the ability to bypass appointment rules.