You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I guide you for today?

USER: Due to some problems I am unable to travel the trip and it is postpones, so could you please change my flight ticket booking?

ASSISTANT: May I know your name?

USER: Thank you and I am Dennis Allen, check with this name.

ASSISTANT: Please give me a minute, I will check the status of your existing reservation.

USER: Sure, take your time.

ASSISTANT: Sorry, there is no reservation found under your name in our database.

USER: Not a problem with that one, thank you for your kind service.

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

USER: Welcome.