You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I serve you?

USER: I want to book a ticket from AUS to DCA. Could you book a ticket?

ASSISTANT: Sure, We are here to help you. When would you like to travel?

USER: Departure is on Aug, 11 and return date is Aug, 13.

ASSISTANT: Do you need any halt?

USER: I need a halt.

ASSISTANT: May I know your name?

USER: My name is Thomas Campbell.

ASSISTANT: There are no flights found on your desired routes.

USER: Thanks.

ASSISTANT: Thank you for opting us.