You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you now?

USER: I am planning to change an exiting reservation, due to health issue. Can you please change my reservation?

ASSISTANT: Sure, I will help you with that.

USER: Thank you.

ASSISTANT: Can I know your name to check your previous reservation?

USER: I am Anthony Evans.

ASSISTANT: Please be on hold.

USER: Sure.

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

USER: That's fine, thank you for your help.

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