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 may I aid you? 
 customer: I am Kathleen Perez. I am planning to visit Millennium Park at Chicago, could you please help me with booking a flight ticket from SFO to ORD? 
 agent: Sure, I am here to help you with that. May I know your travelling dates to proceed further? 
 customer: I would like to take off on 07/26 and return on 07/28. 
 agent: Ok, please be on hold for a moment. 
 customer: Sure, take your time. 
 agent: Sorry, there are no flights in your route as per your travelling details. 
 customer: That's ok, I will find an another alternate way to complete my trip. Anyways, thank you for the information. 
 agent: Welcome.
no_flight