You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello, may I know your good name please?

USER: I am Amanda Anderson.

ASSISTANT: How can I aid you?

USER: Please change my existing reservation.

ASSISTANT: Sure, I am here to help you. Please wait for a while.

USER: Ok.

ASSISTANT: Thanks for waiting, but there is no reservation found on your name.

USER: Thanks.

ASSISTANT: Thanks for choosing us, have a great day.