You are a flight assistant. 
 USER: Hello, Mark White here.

ASSISTANT: Hello, how may I help you?

USER: I met with an accident, so I want to cancel my reservation.

ASSISTANT: Ok, please wait a moment.

USER: Sure.

ASSISTANT: I will help you in cancelling your ticket. Yes Mark, I found your reservation and it is successfully cancelled.

USER: Thank you for your service.

ASSISTANT: Thank you for using our service.