For previous months Account Certifications that were already pushed out, You can request the account certifications be reassigned using the Reassignment Request Template within the Account Certification UBI. Request Account Certification Reassignment Quick Reference Guide
If the person will be on leave across a month end when a new Account Certification will be pushed out, you will need to request the role using the Workday System Access Request. You can find a list of the roles that will become the Preparer and Approver here. If this is a temporary role, you will need to use the Workday System Access Request to remove the role once you are no longer responsible the Account Certification.