In principle, results of exams are valid indefinitely. An educational institution may choose to include a limitation on the validity period in the OER. Before the validity of exam results expires, a student may request the examination board to extent the validity period. One can request this through a petition. The examination board is always authorized to reject a petition. Unless exceptional circumstances are at play, the chances of a successful petition are small. One cannot appeal against the expiration of exam results. The validity of the exam results including the corresponding study credit will expire in due time.