You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Justin King here.

ASSISTANT: How can I help you Justin?

USER: Can you please help me in booking the ticket from IAD to AUS?

ASSISTANT: Sure, please share your travelling dates.

USER: Sure, my journey dates are 02/23 and 02/25.

ASSISTANT: Sorry Justin, no flight is available on your route.

USER: That's fine, thank you for giving the information.

ASSISTANT: Thank you for choosing us, have a nice day.