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: Hello. 
 agent: Hello. How may I assist you today? 
 customer: I have booked a ticket last week with your service but now my cousin's wedding have postponed. Can you please change my existing reservation? 
 agent: Sure, I will help you on that. Could you please provide your name to check your previous reservation status? 
 customer: Sure, I am Susan Miller. 
 agent: Ok Susan, please hold on to check. We regret that, there is no reservation found with your name in our records. 
 customer: Ok, no problem. Thank you for your information. 
 agent: Thank you for approaching us, have a great day.
Solution:
no_reservation