You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how may I assist you?

USER: I am Helen Moore. I would like to change my existing reservation, due to my business meeting got delayed. Can you please assist me?

ASSISTANT: Sure, please wait for a minute.

USER: Ok.

ASSISTANT: Unfortunately there is no reservation found with your name.

USER: Ok, thanks for your quick response.

ASSISTANT: Thank you.