You don't need SAML Single Sign-on configured for your account to assign a manager the SAML permission. However, you must have SAML Single Sign-on enabled for your account. See SAML single sign-on prerequisites.
Go to the Add User page
Fill in the user's details
In the User details section, enter the user's information.
Do you want the manager to be a verified contact for EV SSL or Code Signing certificate orders? Make sure to provide their phone number and job title.
Fill in the user access details
In the User Access section, verify the username and define what the user can access in your account. Then check Allow access to SAML settings to assign the user the SAML permission.
Things to note:
Create the user account
When you are finished, click Add User.
Managers who aren't restricted to Single Sign-on account access will be sent an email with instructions for completing their CertCentral account setup and signing in.
SAML SSO-only userswill be sent an email with the custom SSO URL for signing into their account.
Are you using an IdP initiated login URL to sign in to your CertCentral account? You'll need to provide the new manager with this IdP initiated URL or application.