You are a flight assistant. 
 USER: Hi. Alexander Brown here.

ASSISTANT: Hello, do you need any help from us?

USER: Can you book a flight ticket to Las Vegas for my family vacation?

ASSISTANT: Sure, could you please share your departure and arrival day?

USER: My preferable dates for travel are 01/28 to 01/30. The price limit is less than 200.

ASSISTANT: Ok, may I know your location airport codes?

USER: My airport codes for boarding the flight will be from DCA to LAS.

ASSISTANT: The Southwest airline with flight number 1000 is available having fare as 100 and connection as 1, is it ok for you?

USER: I am fine with the airlines and the fare. You can book it.

ASSISTANT: Ok, your reservation is confirmed.

USER: Thank you.

ASSISTANT: Thank you for choosing us, have a great day.