You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I address you?

USER: I am David hill and I want to cancel my recent reservation due to health issue.

ASSISTANT: Sure, please wait a moment I will check and get back to you.

USER: OK.

ASSISTANT: Thanks for waiting. There is no reservation found with your name.

USER: Thank you.

ASSISTANT: Thanks for choosing us.