You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hi.

USER: I am Steven Hill.

ASSISTANT: how can I help you?

USER: I want to change my existing reservation, because of client meeting in my office. Please help me with that.

ASSISTANT: Sure, Just a second please.

USER: Ok.

ASSISTANT: no reservation found on your name Mr. Steven Hill.

USER: It's ok. Thank you for your service.

ASSISTANT: Thank you.