You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I be a help for you?

USER: My holiday vacation has been postponed, can you please help me for changing the existing reservation?

ASSISTANT: Sure, I will help you with that.

USER: Thank you.

ASSISTANT: May I know your good name please?

USER: Sure, my name is Kevin Lee.

ASSISTANT: Please wait for a moment.

USER: Ok.

ASSISTANT: Sorry, there is no reservation found on your name in our database to change the existing reservation.

USER: No problem, thank you for your information.

ASSISTANT: You are most welcome. Have a great day.