You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I be a help for you today?

USER: I would like to do some changes in my existing reservation which was booked on my name Anthony Collins.

ASSISTANT: Sure, hold on for a moment, let me check.

USER: Ok, please check.

ASSISTANT: I am sorry Anthony, there are no reservations with your name. Do you want to book a new reservation?

USER: No, thank you.

ASSISTANT: Thank you, have a good day ahead.