You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: Need your assistance for booking a flight ticket to IAD with a direct flight.

ASSISTANT: Sure, please share your travel dates.

USER: My travelling dates are on Dec 12 and 14.

ASSISTANT: May I know your source airport code?

USER: I am boarding from AUS.

ASSISTANT: Do you have any preferences?

USER: No.

ASSISTANT: May I know your name?

USER: My name is Anthony Martin.

ASSISTANT: Sorry, I did not find any flights for you.

USER: Ok, thanks for your assistance.

ASSISTANT: Thank you for reaching us.