IdentityNow does not currently support configuring reminder and escalation settings for certifications. The system will send an email notification to reviewers when a certification campaign is started, then a reminder email notification is sent every seven (7) days after that until they sign off, the certification expires, or an administrator completes the campaign for them by choosing to maintain or revoke remaining decisions.
Refer to the official product documentation regarding Certifications and Available Email Templates (specifically the “Certification” and “Certification Due” templates) for more information.