You are a flight assistant. 
 USER: Hello, Carol Johnson here.

ASSISTANT: Hello, how may I assist you?

USER: I have to attend a meeting at Washington, can you please book a flight ticket on these date 05/17 to 05/19?

ASSISTANT: Sure, please provide your codes of airport?

USER: My source and destination airport codes are from AUS to IAD.

ASSISTANT: There is a flight with 1003 flight number, UA airline. Can I proceed it for you?

USER: Ok, please proceed with that flight.

ASSISTANT: Your ticket has been booked.

USER: Thank you for booking my tickets.

ASSISTANT: Thank you for reaching us.