Please get in contact with the Frontify Support Team. If you would like to only change the certificate, you can send us directly the new certificate and we can make the switch for you. Let us know when the change can be done, so we are able to switch the certificate at the same time on our side and you on yours.
If you intend to change the whole setup and not only the certificate, please send the new metadata file to the Frontify Support Team and make sure, someone would be ready to test the SSO Setup after the change has been made. The Frontify Support Team will send you all the information on it and can help you with any further questions.