You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you today?

USER: Please change my existing reservation due to some health issues?

ASSISTANT: Sure, I am glad to help you with that. Can I know your name to check your previous reservation?

USER: Sure, I am Elizabeth Hill.

ASSISTANT: Please wait a moment to check.

USER: Sure.

ASSISTANT: We regret to inform you that, there is no reservation found on your name in our records.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: Thank you for approaching us, have a great day.