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

[Q]: customer: Hi. 
 agent: Hello, how may I aid you at this moment? 
 customer: I would like to change my existing reservation, can you please help me in changing? 
 agent: Sure, we are here to help you. May I know your good name? 
 customer: Anthony Thomas. 
 agent: Ok, please wait for a minute. 
 customer: Sure. 
 agent: Thanks for waiting, there is no active reservation found on your name. 
 customer: Ok, not an issue. Thank you. 
 agent: Thank you for choosing us.
[A]: no_reservation


[Q]: customer: Hello. 
 agent: Hello. How can I help you today? 
 customer: My name is Michelle Green, I just need your help in changing my existing reservation details. 
 agent: Sure, please wait for a while. 
 customer: Ok. 
 agent:  I haven't found your previous reservation in our portal to change further. 
 customer: That's ok, thank you for the information. 
 agent: Thank you for opting us.
[A]: no_reservation


[Q]: customer: Hello. 
 agent: Hello. 
 customer: I am Mary Smith. 
 agent: How can I assist you? 
 customer: I am going to Houston, TX-HOU to purchase a vintage car from a dealer. Can you hold me a ticket? 
 agent: Sure, may I know your source airport code please? 
 customer: My source airport code is Atlanta, GA-ATL. 
 agent: Please provide the travel dates. 
 customer: My travelling dates are from 11/24 to 11/26. 
 agent: Frontier airlines is having a flight on that route with travel charge of 200, shall I proceed for booking? 
 customer: Please proceed for booking. 
 agent: Your ticket has been booked with flight-1002, have a safe journey. 
 customer: Thanks for your help. 
 agent: Thank you for choosing us.
[A]:
book