You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you today?

USER: I want to change my existing reservation, please help me with this?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: May I know your good name for checking previous reservation in our database?

USER: I am Raymond Hall.

ASSISTANT: Please wait for a moment.

USER: Sure.

ASSISTANT: Sorry Raymond Hall, there is no reservation found as per your name in our database.

USER: No problem, thank you.

ASSISTANT: Thank you for reaching us.