You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I support you for the day?

USER: I would like to change my reservation as my client meeting got postponed, so please help me to change it.

ASSISTANT: Sure, I am here to help you.

USER: I made a reservation earlier on the name of Thomas White.

ASSISTANT: May I know your good name? Please wait for a moment.

USER: Sure.

ASSISTANT: Sorry, we found no reservation on your name.

USER: No problem, thanks for your support.

ASSISTANT: Thank you for choosing us. have a great day.