You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, this is online flight booking agency? How may I assist you?

USER: Due to my ill health, I could not travel to Dallas, can you please cancel my recent reservation to Dallas?

ASSISTANT: Sure. We do deal in cancel of flight reservations. Please hold on for a moment.

USER: Ok, please check my reservation.

ASSISTANT: But first I need to know your name.

USER: My name is Dennis Johnson.

ASSISTANT: Thank you Dennis. Your request is under process. I found a reservation and I have cancelled it.

USER: Thank you for cancelling my ticket.

ASSISTANT: Thanks for approaching us.