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 at this moment? 
 customer: I am Pamela Walker here. I am planning to visit a Houston city to meet my grandfather in IAH from LAS. Can you find a flight ticket for me? 
 agent: Sure Pamela Walker, I will help you with that. Can I have your travel dates please? 
 customer: Ok, my preferable dates are on 12/19 and back on 12/21. 
 agent: Ok Pamela Walker, please wait a moment to check flight availability. 
 customer: Sure. 
 agent: AA airlines running a flight in your route with connection 1 and the fare of the ticket is 200. Shall I proceed with booking? 
 customer: Yes, you can reserve the ticket. 
 agent: Ok Pamela Walker, your ticket booking has done and the flight number is 1021. 
 customer: Thank you for spending your time. 
 agent: Thank you for choosing us, have a great journey.
book