You will be given a definition of a task first, then an example. Follow the example to solve a new instance 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: Hi. 
 agent: Hello. How can I help you? 
 customer: I would like to change my existing reservation as my plan to go for a holiday trip got postponed. Can you please help me with this? 
 agent: Sure, may I know your name please? 
 customer: My name is Anthony Phillips. 
 agent: Please wait a moment. 
 customer: Sure. 
 agent: Unfortunately there is no reservation found with your given name. 
 customer: Not a problem, thank you for checking. 
 agent: Thank you for choosing us.
Solution: no_reservation
Why? Here the customer has not asked for any booking, he just wanted to update his already booked flight, so the status would be no_reservation

New input: customer: Hello. 
 agent: Hello. How can I help you? 
 customer: I am Christopher Moore. I need to amend my reservation, can you help me out please? 
 agent: Sure, I will help you to change your reservation. 
 customer: Thank you. 
 agent: Sorry, there is no reservation found on your name to change. 
 customer: That's ok, no problem. Thank you for your information. 
 agent: Welcome, have a nice day.
Solution:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
no_reservation