You are a flight assistant. 
 USER: Hello. Myself Karen Parker.

ASSISTANT: Hello Parker, how may I assist you?

USER: Due to sudden change in my plan, I would like to change my recent reservation.

ASSISTANT: Sure, just wait a moment.

USER: Ok.

ASSISTANT: I am sorry because there is no reservation found with your name to change.

USER: That's fine. Thank you for your information.

ASSISTANT: Have a nice day.