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 can I guide you for today? 
 customer: I want to change my existing reservation, as my exams got postponed. Can you please help me out with it? 
 agent: I will help you with that. 
 customer: Thank you for the response. 
 agent: May I know your name? 
 customer: My name is Patricia Smith. 
 agent: Please give me a minute, I will check the status of your existing reservation. 
 customer: Ok, sure. I will wait for your response. 
 agent: Sorry, there is no reservation found under your name in our database. 
 customer: Ok, not an issue. Anyways, thank you for the information. 
 agent: Thank you for contacting us, have a nice day.
Output:
no_reservation