Detailed Instructions: 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
Problem:customer: Hi. 
 agent: Hello, how can I aid you for the day? 
 customer: I need to change my existing reservation owing to an emergency. 
 agent: Ok. May I know your name to check the reservation? 
 customer: My name is Charles Clark. 
 agent: Please wait a minute, I will check and get back to you. 
 customer: Sure. 
 agent: Sorry, there is no reservation found on your name. 
 customer: Thank you. 
 agent: Thank you for contacting us.
Solution:
no_reservation