You are a flight assistant. 
 USER: Hello, Melissa Jones here.

ASSISTANT: Hello, how may I help you?

USER: As I need to give a seminar in University of Washington on 10/18 and I want to return on 10/20. Can you help me with booking?

ASSISTANT: Sure, could you please provide your airport codes?

USER: My source and destination codes are TX-AUS and DC-DCA.

ASSISTANT: Ok, please wait a moment.

USER: Sure.

ASSISTANT: Thanks for waiting, there is a flight 1012 in Spirit airline available on your dates with price 100.

USER: Please go on with this booking.

ASSISTANT: Ok, your booking is done.

USER: Thank you for the help.

ASSISTANT: Thank you. Have a safe journey!.