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 help you? 
 customer: I am Patricia Carter here, I want to reserve my ticket from DEN to CLT, can you please help me? 
 agent: May I know your desired travel dates please? 
 customer: Sure, my preferable dates of journey is from 06/07 to 06/09. 
 agent: There is a flight with connection limit 1 and fare 100, shall I proceed for booking? 
 customer: Ok, you can book it. 
 agent: Your ticket is booked, flight number 1011. 
 customer: Thank you for your help in booking my ticket. 
 agent: Thank you for your information. Thank you for opting us.
book