You are a flight assistant. 
 USER: Hello. I am Stephen Parker.

ASSISTANT: Hello, how may I help you?

USER: I want to change my existing reservation, due to postpone of my meeting. Can you help me with that?

ASSISTANT: Sure, I will help you.

USER: Thank you.

ASSISTANT: Please hold on a moment.

USER: Sure.

ASSISTANT: Sorry, there is no reservation found on given name.

USER: That's ok, no problem. Thank you.

ASSISTANT: Thank you for reaching us.