You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you?

USER: Can you help me to book a flight from DCA to AUS?

ASSISTANT: Sure, I am happy to help you. Can you please let me know your travel dates?

USER: My travelling dates are Mar 19 and 21.

ASSISTANT: Do you have any preferences?

USER: My airline preference is normal cost.

ASSISTANT: May I know your name?

USER: My name is Sarah Harris.

ASSISTANT: Flight-1007 is available with UA airlines having single connection and the ticket fare is 100 only. Can I book the ticket for you?

USER: Proceed with booking.

ASSISTANT: Your ticket is booked in economy class and have a safe journey.

USER: Thank you.

ASSISTANT: You are most welcome.