You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: I want to change my existing reservation, due to some personal issue. Can you help me?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: May I know your name please to check your reservation status?

USER: Ok, I am George Young.

ASSISTANT: Please wait for a moment.

USER: Sure.

ASSISTANT: George Young, no reservation has been found on your name in our database.

USER: Ok, not an problem. Thank you for your information.

ASSISTANT: Thank you for choosing us.