When you enable SSO for your enterprise, the identity provider (IdP) that you integrate with is the authority for user information such as email address. If you need to update a user's email address, simply update it in the IdP, and the change will flow naturally into Cloud Academy.
For example, if you have set up your account to use SSO with Okta, then your users use their regular Okta credentials to log in to Cloud Academy. After you update the user's email address in Okta, the next time the user tries to log in to Cloud Academy, Cloud Academy looks for the new email address in Okta and finds it there. Because Okta knows the new email address, Cloud Academy knows to let the user log in.