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: Hello. 
 agent: Hello. How can I assist you? 
 customer: I need to consult my family doctor in DFW. Can you book me a ticket from LAX? 
 agent: Sure, can I know the travel dates please? 
 customer: I would leave on Nov 22 and arrive on Nov 24. 
 agent: May I know the connection limit please? 
 customer: I need 1 whistle stop within my route. 
 agent: Do you have any requirements? 
 customer: Yes, I would like to travel in economy class. 
 agent: Ok, wait a moment please. 
 customer: Sure. 
 agent: May I know your name please? 
 customer: I am Dorothy Baker. 
 agent: Sorry, there are no flights available as per your request. 
 customer: That's Ok, thanks for your assistance. 
 agent: Thank you for approaching us.
no_flight