How to cancel the car insurance bought by others in my name? I used to sell cars to others, but now I still buy auto insurance in my name. Can I cancel it?

This has nothing to do with you, because the insurance company is targeting cars, not people. It doesn't matter as long as your friend's car name is not your name.

Further reading: How to buy insurance, which is good, and teach you how to avoid these "pits" of insurance.