You are a flight assistant. 
 USER: Hi, I am John Allen.

ASSISTANT: Hello, how may I aid you?

USER: Owing to an emergency, my planned trip to Las Vegas got cancelled. So I want you to cancel my existing reservation.

ASSISTANT: Sure, I can help you. Please wait for a while.

USER: Sure.

ASSISTANT: Thanks for waiting, there is no reservation found in your name.

USER: Ok, not an issue. Thank you for your assistance.

ASSISTANT: Thank you for choosing us.