You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you?

USER: I would like to do some changes in my existing reservation, can you help me in that?

ASSISTANT: Please can I know your name to proceed to the reservation page?

USER: Sure, the ticket has been reserved on the name John Clark.

ASSISTANT: Ok, thank you for waiting.

USER: My pleasure.

ASSISTANT: Sorry, there is no reservation been found on your name to amend the reservation.

USER: That's ok, no problem. Thank you for the information.

ASSISTANT: Thank you for choosing our agency.