You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you today?

USER: I want to travel from DCA to AUS. Can you help me to book a flight ticket?

ASSISTANT: Sure, can you share me your travelling dates?

USER: I want to fly in the flight on June 11 and June 13.

ASSISTANT: Do you have any airline preference?

USER: I want to travel in normal-cost airline.

ASSISTANT: May I know your name please.

USER: Jason Miller.

ASSISTANT: Is there any other specifications?

USER: No.

ASSISTANT: Sorry, no flights are found on your travel dates.

USER: That's ok. Anyways, thank you.

ASSISTANT: Thank you for reaching us.