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 may I assist you today? 
 customer: I am Eric Green. I would like to book a ticket from PHX to BOS, can you please help me out? 
 agent: Sure, Can you confirm your planned trip dates? 
 customer: I am travelling on these dates July 3rd and 5th. 
 agent: Do you have any another specifications on this journey? 
 customer: I need a single connection limit. 
 agent: Hawaiian Airlines is providing a flight for you with fare 100 and connection limit is 1. Can I proceed with this booking? 
 customer: I prefer departure afternoon flight and arrival morning flight. 
 agent: Your Depature time is 17.00 PM and arrival time is 8.00 AM. 
 customer: Ok, you can proceed. 
 agent: Your ticket reservation done with the flight number 1021. 
 customer: Thank you for your services. 
 agent: Welcome, thank you for reaching us.

book