You have 2 options:
1. Have the user go to the login page (https://app.5starstudents.com/login) and follow the "Forgot your password" link. They can enter their email address and receive instructions to reset their password
2. Go to the Users page (under the Manager menu). Locate the user's existing account and delete it. Then, send them a new account invitation.
If you need further assistance, please contact us directly at firstname.lastname@example.org