Teacher: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
Teacher: Now, understand the problem? Solve this instance: customer: Hi. 
 agent: Hello. How may I guide you today? 
 customer: I need to book a ticket from DFW to PHL. 
 agent: Sure, I will help you with that. Can you please share your preferable journey dates? 
 customer: Depart is by Sept, 7 and return date is Sept, 9. 
 agent: May I know your name please? 
 customer: I am Kathleen Phillips. 
 agent: Do you have any other specifications? 
 customer: I prefer economy class flight. 
 agent: Please wait for a minute. 
 customer: Ok. 
 agent: I found a ticket for you with price of 200, flight number is 1001 in economy class and connection is 1. 
 customer: May I know depart time? 
 agent: Your depart time is afternoon. 
 customer: Please book a ticket. 
 agent: I confirmed your ticket successfully. 
 customer: Thank you. 
 agent: Thank you for reaching us.
Student:
book