Can your auto insurance policy be changed without your consent?

Generally, yes.

It is not uncommon for an insurance company to change the terms and conditions of the policies that it issues. For the most part, coverage and rate changes have to be approved by the state insurance regulatory authority. This is because the regulator wants to be sure that the coverage provided is commensurate in the protection that the policy provides to the premium that is charged.

Any changes in coverage normally occur at the time of renewal of the policy. You are certainly free to reject the proposed chages by seeking coverage with another insurer.