Canceling the insurance policy on a motor vehicle does not affect a contemporaneous cancellation of the registration on that vehicle. The registrant must deal directly with the Registry of Motor Vehicles, either in person, by phone or by mail.
To cancel the registration on a particular vehicle, a registrant should return the license plates to the Registry and receive a Plate Return Receipt. A registrant who does not have possession of those plates should obtain from the Registry a Form C19, "Lost Plate Affidavit for Cancellation of Registration."
Obtaining either a Plate Return Receipt or a processed Form C19 will effectuate a cancellation of the registration on that vehicle. An insurer, in order to cancel or revoke an insurance policy on a motor vehicle, must give electronic notice to the Registry. If the Registry does not receive a new certificate of insurance covering the same vehicle within the following 23 days, it will mail notice to the registrant that unless a new certificate is provided within the ensuing 10 days, the registration on that motor vehicle will be revoked.