You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

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

ASSISTANT: Sure, may I know your good name?

USER: I am Charles Anderson.

ASSISTANT: Please wait for a moment.

USER: Sure.

ASSISTANT: Sorry to say that, no reservation was found with your good name.

USER: No problem, thanks for your information.

ASSISTANT: Thank you for reaching us.