Cancellation of registration: procedural filing, Commissioner notice and specified effective date with continuing post-cancellation obligations. Cancellation requires an application in Form DVAT-09 within thirty days of prescribed events; the applicant specifies the desired effective date, but the Commissioner may notify a different date. The Commissioner serves a proposed-cancellation notice in Form DVAT-10 and, upon cancellation, specifies the effective date in Form DVAT-11 and may impose post-cancellation compliance obligations. Pending or initiating proceedings do not abate. Prior rules requiring surrender or delivery of the registration certificate have been omitted.