You can cancel your auto insurance policy at any time if you want too.
All you have to do is give the auto insurance company proper notice that you plan to cancel the auto insurance policy.
You're not obligated to stay with the same auto insurance company even if you just got the auto insurance policy and can switch auto insurance companies at any time.
However some auto insurance policies being canceled too soon may cause you to have a bad auto insurance score which can affect your rates on getting a new auto insurance policy with another company.
Also if you cancel your auto insurance policies too often and switch auto insurance companies too often it may cause the new auto insurance company to not want to insure you because they figure it's not worth it to them to sign you up if you're gonna switch too soon.
It's recommended to stay with your current auto insurance company for at least 6 months to a year before switching auto insurance companies.
You can also cancel any other insurance policies such as homeowners insurance, health insurance, renters insurance etc at any time.