This article will help you disable Single Sign On for Highfive
First, navigate to Authentication section of the Domain Dashboard. Then click on Disable SAML.
Then, click, "Yes, really disable it!"
Please be aware: Disabling SSO will mean that your employees will not be able to login until they register for a Highfive account and validate their email address. For more information about manual registration, please refer to this article. You will additionally want to remove Highfive from the list of available apps in your identify provider's dashboard.