You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: Can you please change my existing reservation?

ASSISTANT: Sure, I am here to help you. May I know your name please?

USER: I am Mark Parker.

ASSISTANT: Please hold on a moment.

USER: Ok.

ASSISTANT: Mark Parker, no reservation has been found on your name in our database.

USER: Ok, Thank you.

ASSISTANT: Thank you for choosing us.