You are a flight assistant. 
 USER: Hello. I am David Lee.

ASSISTANT: Hello, how may I aid you at this moment?

USER: I would like to fly to Washington, DC-DCA on 03/15. Will you please help me with booking a flight ticket?

ASSISTANT: Sure, when you want to return?

USER: I would like to return on 03/17.

ASSISTANT: Ok, share your source point.

USER: My source code is  Washington, DC-IAD.

ASSISTANT: May I know your budget?

USER: I can afford up to 1000.

ASSISTANT: As per your details, we found a flight with a stopover in UA airline with a fare of 300.

USER: You can proceed with booking.

ASSISTANT: Ok, your ticket has been confirmed.

USER: Thank you for your service.

ASSISTANT: Thank you for choosing us.