You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: My business trip has been postponed.Can you please help me for changing the existing reservation?

ASSISTANT: May I know your name please?

USER: Sure, my name is Samantha Adams.

ASSISTANT: Sorry, no reservations has been found.

USER: Ok, It's fine. Thank you for your information.

ASSISTANT: Thank you for visiting us.Have a nice day.