You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Barbara Carter.

ASSISTANT: How may I assist you?

USER: I need to book a flight ticket from DCA to LAX, Can you please help me for booking?

ASSISTANT: Sure, I will help you. Can I have your planned travel dates please?

USER: I would like to travel on 04/21 to return on 04/23.

ASSISTANT: Please wait a moment, I will find the availability of flights.

USER: Sure.

ASSISTANT: Thank you for your waiting, I found a flight for you in Southwest airlines with fare 100. Can I book your ticket?

USER: Ok, proceed for booking.

ASSISTANT: Ok, your booking is confirmed with flight number 1021.

USER: Thanks for your information.

ASSISTANT: Thank you for choosing us.