You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello, how can I serve you now?

USER: I want to change my existing reservation due to postpone my board meeting.

ASSISTANT: Ok, I will help you to change your reservation.

USER: Thank you.

ASSISTANT: May I know your good name?

USER: Katherine Mitchell here.

ASSISTANT: Please wait for a moment.

USER: Sure.

ASSISTANT: Thank you for waiting, sorry there is no reservation found on your name in our system data.

USER: No problem. Thank you.

ASSISTANT: Thank you for visiting us, have a nice day ahead.