You will be given a definition of a task first, then some input of the task.
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: Hello. I am Betty Jones. 
 agent: Hello, how may I assist you? 
 customer: I want to cancel my recent reservation, can you please help me with this? 
 agent: Sure, please wait for a moment. 
 customer: Sure, take your time. 
 agent: Sorry, there is no reservation found on your name in our database to cancel. 
 customer: Ok, no problem. Thank you for your information. 
 agent: You are welcome.
Output:
no_reservation