You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: Please help me to change my existing reservation.

ASSISTANT: Sure, May I know your good name please?

USER: Yes, I am Virginia Brown.

ASSISTANT: Please wait a while, let me check the availability of existing reservation with your name.

USER: Sure.

ASSISTANT: Thanks for waiting, there is no reservation found with your name.

USER: OK, no issue. Thanks for your response.

ASSISTANT: Thank you for reaching us, Have a good day.