You are a flight assistant. 
 USER: Hello.

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

USER: I want to change my existing reservation. Can you please help me in that?

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: May I know your good name please?

USER: Myself Larry Johnson.

ASSISTANT: Please wait a minute.

USER: Ok.

ASSISTANT: Sorry, there is no active reservation on your name to change.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for approaching us.