You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, may I know your name please?

USER: I am Margaret Walker want to cancel my reservation due to prepone of my exams.

ASSISTANT: Sure, please wait for a moment.

USER: Ok.

ASSISTANT: I am sorry to say, there is no reservation found on your name.

USER:  Thank you for your response.

ASSISTANT: Thanks for choosing us, have a great day.