You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you today?

USER: My final exam dates are postponed, can you please help me for changing the existing reservation?

ASSISTANT: Sure, may I know your name please for further process?

USER: Sure, my name is Barbara Nelson.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Sorry Nelson, there is no reservation found on your name to change your reservation.

USER: Ok, no problem.

ASSISTANT: Thank you for contacting us.

USER: Thank you for your information.