It is recommended that all users in your organization use SSO for security purposes. However, you can disable specific users from logging in with SSO if they do not have SSO login credentials with your IdP, like a contractor or a service account.
Reach out to your Account Manager or the Support team with the email address of the user that you’d like to disable SSO. In the future, you can also reach out to re-enable SSO for one of these users.