Given the task definition and input, reply with output. In this task, you are given a conversation between a flight agent and the customer. You are given 4 options and you need to select the goal of the conversation. It is provided as part of customer's context, which has to be one of the following: `book`: Make a new reservation, `cancel`: Cancel an existing reservation, `no_flight`: No flight found for the customer's preference, `no_reservation`: No reservation / No change / No cancellation was made in the conversation, mostly enquiring details

customer: Hi. 
 agent: Hello, how may I assist you today? 
 customer: Owing to an emergency, my meeting with client got cancelled. So I want you to cancel my existing reservation. 
 agent: Sure, we are here to help you with cancellation. To proceed further, May I know your name? 
 customer: Sure, John Edwards here. 
 agent: Please wait for a while. 
 customer: Sure. 
 agent: Thanks for your time, we found a reservation on your name and it is successfully cancelled. 
 customer: Thank you. 
 agent: Thank you for choosing us.
cancel