You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Barbara white.

ASSISTANT: How can I assist you?

USER: I want to change my reservation.

ASSISTANT: Sure White, please wait a moment.

USER: Sure.

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

USER: That's ok.

ASSISTANT: Thank you for approaching us.

USER: Thank you.