You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, can I serve you today?

USER: I would like to enjoy the night life of Las Vegas, so please book me a flight ticket with in price 500.

ASSISTANT: Sure, may I know your journey dates?

USER: Sure, I will start on 05/19 and return on 05/21.

ASSISTANT: Sure, do you have any preferences?

USER: I need a flight with a halt.

ASSISTANT: Could you share your journey points/.

USER: I will depart from DCA and land at LAS.

ASSISTANT: Please wait a minute.

USER: Ok.

ASSISTANT: We found a flight on Delta airline, flight number 1007 with the fare of 100.

USER: Please confirm it.

ASSISTANT: May I know your name?

USER: I am Elizabeth Davis.

ASSISTANT: Your ticket has been booked.

USER: Thank you for your help.

ASSISTANT: Thank you for opting us.