You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you now?

USER: Can you please change my existing reservation?

ASSISTANT: Sure, I am here to help you in changing your existing reservation. Please, provide me your name to check your reservation status.

USER: Sure, I am Carol Wilson.

ASSISTANT: Ok, please wait for a while. I will check and get back to you.

USER: Sure.

ASSISTANT: Sorry to say that, we have not found any reservation on your name in our records.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: Thank you for opting us, have a good day.