You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: My name is Stephen Johnson. As my business trip got postponed to other dates, I would like to change my existing reservation.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Sorry, there is no reservation found by your name.

USER: That's fine. Thank you for your information.

ASSISTANT: Thank you and have a nice day.