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
Q: customer: Hi. 
 agent: Hello, how may I lend a hand to? 
 customer: I need to change my existing reservation as my trip got postponed, Can you please help me with that? 
 agent: Sure, I am here to help you for this. Could you please mention your name? 
 customer: Kevin Williams here. 
 agent: Please wait for a while, let me check your reservation status in our records. 
 customer: Sure. 
 agent: Sorry for inconvenience, no reservation is found with your criteria. 
 customer: Ok, no problem. Thanks for your information. 
 agent: Thank you very much for contacting our agency.
A:
no_reservation