You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I am David White. Due to some important work, I need to cancel my reservation.

ASSISTANT: Sure, please hold on for a moment.

USER: Sure.

ASSISTANT: David White, there is no reservation found on your name to cancel.

USER: It's ok, tank you.

ASSISTANT: Thank you for reaching our service.