The Illinois Homeowner Exemption Certificate of Error application is a form used by homeowners to request a correction to their tax bill. The application is used when homeowners have overpaid their taxes due to an error on the part of the Illinois Department of Revenue. There are two types of applications: a correction of an error on a Homeowner Exemption Certificate and a correction of an error on a Senior Citizen Assessment Freeze Exemption Certificate. The application must be completed in full and submitted to the local county assessor’s office along with supporting documentation. If approved, the applicant will receive a refund of the overpaid taxes.