Anyone with access to the audit submission can make changes to the Auditee and Auditor Certifying Officials, as well as add additional Audit Editors.
Keep in mind that you can only have one Auditee Certifying Official and Auditor Certifying Official per single audit submission. These can't not be the same individuals.
These instructions walk you through making changes to user roles. Once you have completed these steps, users must log out and log back in to their account for the changes to take effect.