You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I aid you at this minute?

USER: Could you please change my existing reservation due to postpone of my trip?

ASSISTANT: Sure, I am here to serve you.

USER: Thank you.

ASSISTANT: May I know your name?

USER: My name is Robert Miller.

ASSISTANT: Ok, wait for a minute.

USER: Sure.

ASSISTANT: I regret to say that, there is no reservation found on your name in our database.

USER: Not a problem, thanks for checking.

ASSISTANT: Thank you for consulting us.