You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you at this moment?

USER: I would like to book a ticket from AUS to invite some of my friends at IL-ORD for my wedding, please help me with it.

ASSISTANT: Sure. I will help you. Can I have your travelling dates?

USER: I want to fly on 07/31 and will return on 08/02.

ASSISTANT: May I know your name?

USER: I am Thomas Hernandez.

ASSISTANT: Please wait for a moment.

USER: Sure.

ASSISTANT: Sorry Thomas. There is no flights scheduled on the dates which you are planning to travel.

USER: Fine, thanks for the information.

ASSISTANT: Welcome. Thank you for approaching us.