I have an enterprise client that has internal copies of the certificates that its users can have access to. They had a programmed date to update ours on sept 29, on its last valid date, but it was updated today. And I am searching for a way to reinstall the previous edge certificate.
If this was a Cloudflare installed edge certificate from Universal SSL or Advanced SSL, you can’t. Certificates are updated ~30 days before expiry which is normal practise to allow time to resolve any problems.
As your client has an Enterprise plan, they can upload their own certificates to the Cloudflare edge if they want to control certificate issuance themselves.