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 help you? 
 customer: I have to do some modification in my previous flight ticket booking that there is a sudden event held at my home town, so I am unable to travel the trip. Can you please help me out in changing my reservation? 
 agent: Sure, I am here to help you. May I know your name? 
 customer: Thank you and myself Brian Wilson. 
 agent: Ok, please wait for a moment. 
 customer: Sure. 
 agent: Thank you for your time, There was no reservation found on your name in our database. 
 customer: It's ok, thank you for your help. 
 agent: Thank you for choosing us.
no_reservation