How do you write a business letter to a travel agent cancelling a trip?

When writing a business letter to a travel agent to cancel a trip, it is important to include the booking reference number, trip details, and the reason for cancellation. Begin with a formal salutation and clearly state that you are canceling the trip. Provide any necessary information for processing the cancellation, such as requesting a refund or rescheduling the trip. End the letter with a polite closing and your contact information in case the agent needs to reach you for further clarification.