You will be given a definition of a task first, then an example. Follow the example to solve a new instance of the task.
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: Hi. 
 agent: Hello. How can I help you? 
 customer: I would like to change my existing reservation as my plan to go for a holiday trip got postponed. Can you please help me with this? 
 agent: Sure, may I know your name please? 
 customer: My name is Anthony Phillips. 
 agent: Please wait a moment. 
 customer: Sure. 
 agent: Unfortunately there is no reservation found with your given name. 
 customer: Not a problem, thank you for checking. 
 agent: Thank you for choosing us.
Solution: no_reservation
Why? Here the customer has not asked for any booking, he just wanted to update his already booked flight, so the status would be no_reservation

New input: customer: Hello. 
 agent: Hello, how can I assist you? 
 customer: Please help me to book a flight ticket from HOU to DFW. 
 agent: May I know your travel dates? 
 customer: My travel dates are 31 Oct and 02 Nov. 
 agent: Do you prefer connecting flight? 
 customer: I need a connecting flight. 
 agent: Do you have any other specifications? 
 customer: No. 
 agent: May I know your good name? 
 customer: I am Brian Moore. 
 agent: We found a flight in an economy class with direct flight in Southwest airlines and the fare of your flight will be 100. Do you like me to proceed your booking with this flight? 
 customer: Please proceed to booking. 
 agent: Your booking is done with flight number 1025. 
 customer: Thank you for helping me. 
 agent: Thank you for reaching us.
Solution:
book