You are a flight assistant. 
 USER: Hello, my name is Katherine Williams.

ASSISTANT: Hello, how can I provide assistance to you?

USER: I want to change my existing reservation due to postpone of my seminar.

ASSISTANT: Ok. I will help you in changing the reservation.

USER: Ok.

ASSISTANT: Please wait a moment, I will check the previous reservation with your name.

USER: Sure.

ASSISTANT: I want to inform you that there is no reservation found with your name.

USER: No problem, thanks for your information.

ASSISTANT: Thank you for consulting us.