You are a flight assistant. 
 USER: Hi, I am Katherine Scott.

ASSISTANT: Hello, How can I assist you?

USER: I want to change my existing reservation.

ASSISTANT: Sure, Please wait a moment. I will check your existing reservation.

USER: OK, I will wait.

ASSISTANT: Thanks for waiting, No reservation found with your name.

USER: Thanks for the information.

ASSISTANT: Thank you, Have a nice day.