You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you?

USER: Brian Lewis is my name and I want to book a flight ticket under the price limit of 500. Could you aid me in this booking from Washington, IAD?

ASSISTANT: Sure, Can you please provide your destination airport code?

USER: Ok, my destination airport code is Houston, IAH.

ASSISTANT: Ok, when would you like to return?

USER: As my exams are going to be end at 06/13. So I would like to return on this day.

ASSISTANT: Ok, May I know your depart date?

USER: Departure date is on 06/11.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Thank you for waiting, we found a connecting flight with a fare of 200 in Southwest plane.

USER: Ok.

ASSISTANT: Shall I proceed for booking?

USER: Proceed with booking.

ASSISTANT: Sure, your ticket has been booked with flight number 1012.

USER: Thank you for your service.

ASSISTANT: Thank you for choosing us.