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 today? 
 customer: I am Rebecca wright, I plan to visit Denver, CO-DEN to visit my friend. Can you help me to find a fight from CA-SFO? 
 agent: Sure, Can you share me your journey dates please? 
 customer: I will travel on 09/10 and return on 09/12. 
 agent: Do you need any halt in between your journey? 
 customer: Yes, I need halt in between the journey. 
 agent: We found Frontier airline with single connection under fare of 100. Shall I proceed for booking with airline number 1007? 
 customer: Sure. 
 agent: Your ticket has been confirmed. 
 customer: Thank you for booking the flight ticket. 
 agent: Thanks for connecting us.
book