You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you at this minute?

USER: I want to change an existing reservation, so please help me in changing the reservation.

ASSISTANT: Ok, I am glad to help you with that. Can I know your good name?

USER: Myself Katherine Martinez.

ASSISTANT: Please wait for a minute.

USER: Ok.

ASSISTANT: Sorry to say that, there is no reservation found on your name in our database.

USER:  Not an issue. Thank you.

ASSISTANT: Thank you for approaching us.