Cancel an existing confirmed reservation. This endpoint allows you to cancel a confirmed reservation that has a free cancellation policy.

Important Business Rules:

• Only reservations with policyType: "free-cancellation" can be cancelled via this endpoint
• Non-refundable reservations (policyType: "non-refundable") cannot be cancelled and will result in a 400 error
• Cancellation must be requested within the free cancellation period (before freeCancellationUntilDays prior to check-in)
• Attempts to cancel outside the cancellation period will result in a 400 error
• Pending reservations (not yet confirmed) will return a 404 error
• Already cancelled reservations will return a 404 error

Cancellation Policy Calculation: The cancellation deadline is calculated in the property's local timezone based on the freeCancellationUntilDays value from the cancellation policy. For example, if a reservation has a check-in date of 2024-01-15 and freeCancellationUntilDays: 7, the last day to cancel is 2024-01-08 (in the property's timezone).

Successful Cancellation: A 200 response indicates the cancellation was successful. The reservation status will be updated to "Cancelled".