You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: My name is David Hill.

ASSISTANT: How can I help you, David?

USER: Due to some health issues, I would like to cancel my reservation. Please help me.

ASSISTANT: Sure, please wait a moment.

USER: Ok, take your time.

ASSISTANT: David, no reservation has been found on your name in our database.

USER: Its ok, thank you for the information.

ASSISTANT: Thank you for choosing us.