You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you today from my end?

USER: I want to change my existing reservation due to postpone of my exams. Can you help me in that?

ASSISTANT: Sure, I am here to help you out. Please provide me your name.

USER: Myself Kenneth Clark.

ASSISTANT: Kenneth Clark, please allow me a moment.

USER: Ok.

ASSISTANT: Sorry Kenneth Clark, there is no reservation on your name in our database.

USER: Ok, no problem. Thank you for your information.

ASSISTANT: Thank you for reaching us.