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. I am Sharon Johnson. 
 agent: Hello, how may I succor you? 
 customer: Can you please help me in flight ticket booking from SFO to LAS to attend a client meeting? 
 agent: sure, may I know when do you want to travel? 
 customer: Thank you and my travelling dates are 09/19 and back on 09/21. 
 agent: Ok, please wait for a while. 
 customer: Sure. 
 agent: Thanks for sharing your essentials. There are no flights available on your route. 
 customer: Ok, no issue with that. Thank you for your help. 
 agent: Thank you for opting us. 
 customer: Welcome.
no_flight