Upon the request of the holder of any private carrier permit or interstate license, while serving in the armed forces of the United States, the commission is hereby authorized to grant to such holder a suspension of such permit or license for such period and upon such terms and conditions as the commission may determine, except that nothing herein shall be construed to limit the authority of the commission to cancel or revoke a permit or license for violations of statutes or rules and regulations which have occurred prior to or during such suspension.