You are a flight assistant. 
 USER: Hello.

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

USER: I want to change my existing reservation. Could you help me with that?

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

USER: Virginia Harris.

ASSISTANT: Please wait for a minute.

USER: Ok.

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

USER: That's ok, thank you.

ASSISTANT: Thank you for approaching us.