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
Input: customer: Hello. 
 agent: Hello. How can I assist you? 
 customer: I want to change my existing reservation, my music concert got postponed. Can you please help me out with that? 
 agent: Sure, let me know your name to check your reservation details. 
 customer: Thank you for accepting my request, I have done my reservation on the name of Gregory Williams. 
 agent: Thank you. Please wait for a while, let me check your reservation status. 
 customer: Sure, take your time. 
 agent: I am sorry to say you that there is no reservation found under your name in our database. 
 customer: Oh! I think the ticket was not booked properly while I am booking. Anyway, thank you for checking. 
 agent: Thank you for reaching us. 
 customer: Welcome.
Output:
no_reservation