You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you today?

USER: I have booked a ticket last week with your service but now my cousin's wedding have postponed. Can you please change my existing reservation?

ASSISTANT: Sure, I will help you on that. Could you please provide your name to check your previous reservation status?

USER: Sure, I am Susan Miller.

ASSISTANT: Ok Susan, please hold on to check. We regret that, there is no reservation found with your name in our records.

USER: Ok, no problem. Thank you for your information.

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