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. 
 agent: Hello. How may I help you? 
 customer: I was made a reservation earlier in this week. But I want to change my reservation. Can you please help me for that? 
 agent: Sure, I will help you out. May I know your name please? 
 customer: My name is Christopher Thompson here. 
 agent: Ok, please wait a moment. 
 customer: Ok, I will wait. 
 agent: Sorry, there are no reservations found. 
 customer: Anyway, thanks for the information. 
 agent: Thank you for choosing us.
Output:
no_reservation