The following workflow diagram illustrates the typical flow of the travel reservation system. The workflow consists of reserving air travel, reserving a car, processing payments, confirming flight reservations, and confirming car rentals followed by a success notification when these steps are complete. However, if the system encounters any errors in running any of these transactions, it starts to fail backward. For example, an error with payment processing triggers a refund, which then triggers a cancellation of the rental car and flight, which ends the entire transaction with a failure message.