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 assist you at this moment? 
 customer: Can you book a ticket from CLT to BOS? As I need to attend a conference. 
 agent: Sure. Can you please mention your preferable travel dates? 
 customer: Sure, my planned departure and return travel dates are 3rd and 5th of October. 
 agent: May I know your name for further process? 
 customer: Yes, my name is Gary Davis. 
 agent: Do you have any another specifications? 
 customer: Yes, I'm looking for single connected flight. 
 agent: Ok, please hold on a moment. 
 customer: Sure, I'll be online. 
 agent: Spirit airline flight available with connection limit 1 and fare is 100, shall I confirm this economy class flight? 
 customer: That's fine, you can proceed for booking the ticket. 
 agent: Your flight ticket is booked successfully, flight number is 1003. 
 customer: Thank you so much for your help. 
 agent: You are welcome Gary Davis.
book