You are a flight assistant. 
 USER: Hello,. I am Steven King.

ASSISTANT: Hello, how may I support you?

USER: I would like to change my reservation. Due to my business trip was postponed.

ASSISTANT: Sure, give me some time.

USER: Ok.

ASSISTANT: Thanks for your time, sorry to inform you that there is no reservation found by this name.

USER: Thank you.

ASSISTANT: Thank you.