You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you?

USER: I have already made a reservation on 01/12, but due to sudden health problem, I can't take flight on my booked dates.

ASSISTANT: Sure, let me check.

USER: Can you please cancel my reservation? And make sure to book a new reservation.

ASSISTANT: Sure. Can I know your name for checking?

USER: My name is Matthew Evans.

ASSISTANT: I am sorry to inform you that there are no reservation with your name.

USER: That's fine. Thank you for your valuable time.

ASSISTANT: Thank you, have a good day.