You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you at this moment?

USER: My name is Donald Roberts. Can you help me to book a business class flight to DCA from AUS?

ASSISTANT: Sure, I am here to help you. Can you please provide your journey dates?

USER: Ok, please book a ticket for the dates Sept 11 and 13th respectively.

ASSISTANT: Do you have any other specifications?

USER: No.

ASSISTANT: Wait a moment please.

USER: That is ok. Take your own time.

ASSISTANT: Donald Roberts, there is no flight services are available on this route with your preferences.

USER: That is ok, thank you for providing the information.

ASSISTANT: Thank you for contacting us.