You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. What can I do for you?

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

ASSISTANT: Sure, please help me with your name.

USER: Sure, I'm Catherine Wilson.

ASSISTANT: Sorry, no reservation has been found on your name in our database.

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

ASSISTANT: Thank you for using our services.