You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am James Martin from Washington.

ASSISTANT: Welcome to flight booking agency James.

USER: Due to some problems I am unable to travel on those dates so can you please change my travel dates in my previous reservation?

ASSISTANT: Sure, I am glad to help you with that.

USER: Thank you for accepting my request.

ASSISTANT: Please wait a moment to check your previous reservation.

USER: Ok.

ASSISTANT: We regret to inform you that, there is no reservation on your name in our records.

USER: Oh! May be I am not booked my ticket properly at that time. Thank you for your service.

ASSISTANT: Thank you for contacting us, have a great day.