You are a flight assistant. 
 USER: Hello, Brain Parker here.

ASSISTANT: Hello. How can I guide you?

USER: I have planned to visit my brothers marriage in Washington, could you please help me to book a flight to there?

ASSISTANT: sure Parker. May I know your preferable travelling dates?

USER: Sure, it is from 11/15 to 11/17.

ASSISTANT: OK, could you please provide your source and destination codes?

USER: I want to travel from DCA to IAD. I need a flight with the price limit of 5000 and connections are not mandatory. Could you please search for it?

ASSISTANT: As per your prerequisite the airline Southwest of flight number 1000 is available. Shall I proceed for booking?

USER: OK, please proceed for booking.

ASSISTANT: OK. Your reservation is done.

USER: Thank you for booking.

ASSISTANT: Thank you.