You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Jonathan Clark.

ASSISTANT: How can I help you Clark?

USER: Due to an urgent work, I would like to cancel my trip to Dallas. Can you please help me in cancelling my recent reservation?

ASSISTANT: Sure, please wait for a moment.

USER: Sure, take your own time.

ASSISTANT: Sorry Clark, no active reservation found by your name in our website.

USER: Ok, not an issue. May be my brother has already cancelled my reservation on behalf of me. Thank you for providing information.

ASSISTANT: Thank you for contacting us.