The claim type can be changed by using the Switch Claim Type feature, which can be accessed from the Claim Info sidebar, underneath the "Claim Type" label, and also next to the "Claim Type" field on the Claim Details tab.

You will be asked for the new claim type and also any required changes to the incident type, damage types, contact roles and/or contact liabilities. These options can vary per claim type, so the Switch Claim Type process will guide you through a review of each one, if required, in order to ensure the selections remain valid for the new claim type.