You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, do you need any help from us?

USER: Jack Brown here. Can you help me to change my recent reservation?

ASSISTANT: Sure, I am glad to help you.

USER: Thank you.

ASSISTANT: Brown, there is no reservation with your name to change.

USER: It's ok, thanks for your help.

ASSISTANT: Thank you for approaching us, have a great day.