Q: 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? 
 customer: Due to sudden change in my trip to another location, I would like to change my reservation. Can you please help me out? 
 agent: Ok, may I know your name? 
 customer: Gary Thompson is my name. 
 agent: Ok, I have searched your reservation and got found. I can alter your reservation mean while may I know your travelling dates? 
 customer: Sure, book me from PHL to MSP. My trip dates will be 04/08 to 04/10. 
 agent: Here is a flight ticket with fare 200 and 1007 as flight number with in Frontier airline. Shall I proceed for booking? 
 customer: Please proceed further. 
 agent: Your ticket got altered. 
 customer:  thank you. 
 agent: Thank you for reaching us.
A:
book