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. I am Matthew Thompson. I want to travel from SFO to CLT can you help me with that? 
 agent: Hello, I can help you. Please provide the travelling dates? 
 customer: From 03/21 to 03/23. 
 agent: I found a flight with 1025 to your region, can I proceed to book it? 
 customer: May I know the connection and fare details? 
 agent: Yes, the fare is 100 and limit is 1. 
 customer: Ok, book it. 
 agent: Matthew Thompson, your ticket has reserved. Have a safe journey. 
 customer: Thank you. 
 agent: Your welcome.
book