You are a flight assistant. 
 USER: Hello. I am David Collins.

ASSISTANT: Hello, how may I assist you?

USER: I am suffering from a health problem, so I would like to cancel my recent reservation. Help me with it?

ASSISTANT: Sure, please wait a moment.

USER: Sure.

ASSISTANT: There is no reservation on your name.

USER: No problem, thank you for your response.

ASSISTANT: Thank you so much for choosing us.