Notice is information concerning a fact, actually communicated to a person by an authorized person, or actually derived by him from a proper source, and is regarded in law as "actual" when the person sought to be affected by it knows thereby of the existence of the particular fact in question.

Insurance answer
Your insurance policy will state how the policy may be terminated. Notice must be given by the insurer with a set amount of days. For you, the consumer it is less restricted. You can give notice to the insurer that you no longer want their policy at any time.