You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you today?

USER: Brandon Roberts here, I am a student and I would like to travel Washington to submit my document, can you book a flight ticket on 06/19 and book return ticket on 06/21.

ASSISTANT: Sure, I will help you with that.

USER: Thank you.

ASSISTANT: Can you please mention your preferable airport code names?

USER: My regional airport codes are from SFO to IAD.

ASSISTANT: Ok, please wait a moment, I will check flight availability.

USER: Sure.

ASSISTANT: I have found a flight in this route, airline is UA and flight number is 1004. Shall I confirm this flight ticket for you?

USER: Yes, do proceed.

ASSISTANT: Your flight ticket is booked successfully.

USER: Thank you so much.

ASSISTANT: Thank you for reaching us, have a nice day.