You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: Can you please help me to change my existing reservation, due to my interview has been postponed?

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

USER: Thank you, Donna Lee is my name.

ASSISTANT: Wait a moment please.

USER: Sure.

ASSISTANT: Donna Lee, we haven't found any reservation under your name in our database. Thank you for choosing us.

USER: Ok, thanks for your information.