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: Hello. 
 agent: Hello, How can I serve you? 
 customer: I am Anthony Campbell, I want to book a flight ticket to Washington DC - IAD to attend a wedding event. Please book a ticket from Charlotte, NC - CLT. 
 agent: Sure. 
 customer: I wish to travel on 06/25 and 06/27. 
 agent: Is there any other requirements? 
 customer: Yes, price can be 200 with a connection. 
 agent: We have found a flight from Frontier airline with flight number 1012. 
 customer: Please go for booking process. 
 agent: Your ticket has been reserved. 
 customer: Thanks for your service. 
 agent: Thank you for choosing us.
book