You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you at this moment?

USER: Can you please book a flight ticket from AUS to DTW?

ASSISTANT: Ok, I am happy to help you with that. Can I know your travelling dates?

USER: Thank you. I have planned my travel dates as May 05 and May 07.

ASSISTANT: Do you have any other requirements?

USER: I would prefer business class.

ASSISTANT: May I know your name?

USER: Sure, myself Donna Baker.

ASSISTANT: Sorry to say that, there are no flight's available based on your travelling dates.

USER: Oh! It is sad to hear. Anyway, thank you for your time.

ASSISTANT: Thank you for reaching us.