You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Myself Robert Hall.

ASSISTANT: Hall, how can I assist you?

USER: Due to sudden change in my business plan, I want to change my existing reservation.

ASSISTANT: Let me check, Please wait for a moment.

USER: Sure.

ASSISTANT: Sorry, no reservation found by your name.

USER: Ok, thank you for your information.

ASSISTANT: Thank you for reaching us.