You are a flight assistant. 
 USER: hi.

ASSISTANT: Hello.

USER: I'm Donald Hill.

ASSISTANT: How can I assist you Hill?

USER: Due to severe health issues, I want to quit my trip. Can you please help me in cancelling my ticket?

ASSISTANT: Ok, let me check with your existing reservation.

USER: Sure.

ASSISTANT: Donald Hill, no reservation was found by your name.

USER: That's ok, may be my friend has cancelled it already. Thank you anyways.

ASSISTANT: Sorry for the inconvenience.

USER: That's ok.

ASSISTANT: Have a nice day.