You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How can I assist you?

USER: Due to sudden work at my office, I am unable to travel now. Can you please change my existing reservation?

ASSISTANT: Sure, May I know your name?

USER: Please check the reservation on the name of Carol Brown.

ASSISTANT: Please wait a second.

USER: Sure.

ASSISTANT: Sorry, No reservation found on your name.

USER: Ok, Thank you for your help.

ASSISTANT: Thank you for opting us.