Any person who has signed the application of a minor for a license may thereafter file with the commissioner a verified written request that the license of said minor so granted be canceled. Thereupon the commissioner shall cancel the license of said minor and the person who signed the application of such minor shall be relieved from the liability imposed under Section 63-1-25 by reason of having signed such application on account of any subsequent negligence or wilful misconduct of such minor in operating a motor vehicle.