What is the term for adding additional coverage to an existing policy?

The term for adding additional coverage to an existing policy is commonly referred to as an endorsement or rider. Endorsements are modifications made to the original insurance policy that add or change coverage. These can include additional benefits, new coverage options, or even modifications to existing terms.

Riders are specific attachments to the policy that provide extra benefits or coverages beyond what is included in the standard policy. For instance, a life insurance policy might have a rider that provides for accidental death benefits or a long-term care benefit, enhancing the overall scope of coverage.

While other terms like "policy extension," "supplemental coverage," and "addendum clause" might suggest a form of additional coverage, they do not specifically define the practice of modifying an existing policy with new terms or benefits in the way that endorsements and riders do.