You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Donald Brown.

ASSISTANT: How may I help you?

USER: I am planning to cancel my recent reservation, due to health issue. Can you please cancel my ticket?

ASSISTANT: Sure, I will help you with that.

USER: Thank you.

ASSISTANT: Sorry to say that, there is no reservation found on your name in our database, I think your previous reservation is not done before.

USER: That's fine. Thank you for your service.

ASSISTANT: Thank you for reaching us.