You will be given a definition of a task first, then some input 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: Hello. 
 agent: Hello. How may I help you today? 
 customer: Can you please change my existing reservation? 
 agent: Sure, may I know your name for change in the reservation? 
 customer: Sure, I am Sharon Wright. 
 agent: Please wait a moment. 
 customer: Sure. 
 agent: Thank you for waiting. Sorry, there are no active reservations on your name to change. 
 customer: Thank you for your information. 
 agent: Thank you for reaching our service.
Output:
no_reservation