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. Myself Betty Anderson. 
 agent: Hello, how may I aid you today from my end? 
 customer: I want to change my existing reservation, can you help me? 
 agent: Sure, I am here to help you out. Please allow me a moment. 
 customer: Thank you. I will wait for your response. 
 agent: Sorry Betty Anderson, there is no reservation on your name in our data base. 
 customer: That's ok, no problem. Thank you for the information. 
 agent: Thank you for reaching us.
Output:
no_reservation