I'm assuming this is related to Auto Insurance Policy. Switching auto insurance is done by the new auto insurance provider. If you live in the United States please keep in mind that it is most likely illegal to drive without insurance. That said, if you choose to simply end your car insurance in written letter form I would recommend standard business letter form with the name of the company, the department with which you wish to correspond, followed by its address on the top left of the page. Label it "To Whom It May Concern:" and simply state, "I [name] wish to terminate the insurance policy on policy #[policy number] for my [car color, make, and model], license plate #[number]. Please inform me of any penalties or extra charges associated with this process by contacting me by [state email, phone, or letter] prior to proceeding with any extra charges. If there are no charges associated with the process please terminate the policy as soon as possible and send confirmation by mail to the address enclosed below." Sign, insert your name and address, send letter.
