You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you at this moment?

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

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

USER: Thank you.

ASSISTANT: Can I have the name on which you reserved previously?

USER: Sure, the previous reservation is on the name of John Gonzalez.

ASSISTANT: Ok, please wait a moment and I will check the reservation status.

USER: Sure.

ASSISTANT: Thank you for waiting.

USER: Ok.

ASSISTANT: Sorry John, no reservation found under your name to change.

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

ASSISTANT: Most welcome. Thank you for choosing us, have a great day.