You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you today?

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

ASSISTANT: Sure, I am glad to help you with that.

USER: Thank you.

ASSISTANT: Can I know your name to check your previous reservation?

USER: Sure, my name is Helen Thompson.

ASSISTANT: Sorry, there is no reservation with your name in our records.

USER: Ok, no problem.

ASSISTANT: Thank you for reaching us, have a great day.

USER: Thank you for your information.