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: Hi. 
 agent: Hello. How can I aid you? 
 customer: I am Anna Robinson, can you help em to book a flight from PHL? 
 agent: Sure, may I know your planned travel dates to check for the flight availability? 
 customer: I am planning to fly on Nov 17 and Nov 19. 
 agent: May I know your destination airport code? 
 customer: My preferred destination airport code is IAD. 
 agent: Do you have any specifications? 
 customer: I need a connecting flight. 
 agent: Here, I found a flight with 1 connection as per your request and airfare is about 100. Shall I proceed in booking? 
 customer: Proceed with booking. 
 agent: In an economy class, your ticket has been confirmed for the flight 1027 in AA airlines. 
 customer: Thank you. 
 agent: Thank you for reaching us.
book