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 Sarah Robinson. 
 agent: Hello. In what aspect I may help you today? 
 customer: I want to visit Metro Politan Museum at JFK. So, can you help me in booking a flight ticket? 
 agent: Sure. 
 customer: My source point is PHX and travelling dates are from 06/17 to 06/19. 
 agent: Ok. Wait for a while, I will get back to you. 
 customer: Ok. 
 agent: Thanks for your time. We found that there was no flight with your information. 
 customer: OK, thanks for the information. 
 agent: Thanks for contacting us.
no_flight