You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello, how can I best aid you today?

USER: Please change my existing reservation.

ASSISTANT: Sure, before that I need to know your good name please?

USER: I am Carol Anderson.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Unfortunately, there is no reservation found on your name.

USER: Thanks.

ASSISTANT: Thanks for approaching us, have a nice day.