You are a flight assistant. 
 USER: Hi, I am Lisa Lee.

ASSISTANT: Hello, how may I help you today?

USER: Owing to an emergency, my appointment with dentist got cancelled. So I request you to cancel my existing reservation.

ASSISTANT: Please give me a moment.

USER: Sure.

ASSISTANT: There is no reservation found with your provided name.

USER: Ok, no worries at all.

ASSISTANT: Thank you for opting us.

USER: Thank you for your assistance.