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: Hi. 
 agent: Hello. How can I assist you? 
 customer: I am Emma Young. I am planning to book a ticket from CLT to DFW. Can you please help me out? 
 agent: Ok, may I know your travelling dates? 
 customer: I would like to travel on Mar 10 and return back on Mar 12. 
 agent: Here is a connecting flight with flight number 1029 and fare is 100, providing ticket in economy class. Shall I proceed with booking? 
 customer: That's fine, please proceed the booking. 
 agent: Your booking is done in Spirit airlines. 
 customer: Thank you for your service. 
 agent: Thank you for choosing us.
book