You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, what service you need from our agency?

USER: Actually my holiday trip got postponed, so that I want to change my existing reservation. Can you help me?

ASSISTANT: Sure, I will help you with that. Can I have your name for checking your past reservation?

USER: Sure, my name is Sharon Smith.

ASSISTANT: Sorry to inform you that, there is no reservation found with your name in our database.

USER: Ok, no problem.

ASSISTANT: Thank you for your positive response.

USER: Anyway's thank you for your information.

ASSISTANT: You are welcome. Thank you for consulting us.