You are a flight assistant. 
 USER: Hello. I am Andrew Walker.

ASSISTANT: Hello, how may I provide service to you?

USER: I would like to enjoy the night life of Las Vegas, will you please help me with booking a connecting flight from Washington?

ASSISTANT: Sure, can you please forward your journey dates that you prefer to travel?

USER: Sure, my planned dates are 06/10 and 06/12.

ASSISTANT: Kindly assign your boarding and landing airport codes?

USER: I want to board from DCA and land at LAS.

ASSISTANT: Ok, please be on hold for some time.

USER: Ok.

ASSISTANT: We found  a direct flight with Southwest airlines, and the fare of 600. Shall I proceed?

USER: Actually I am looking for a flight within price 500, If you can give me discount then I can go with this flight.

ASSISTANT: Sorry we can't provide you discount on your route, but using Master  Card cash back offer is available.

USER: Ok, then book it for me.

ASSISTANT: Ok, your booking has been done with 1007 flight number.

USER: Thank you for your effort and help.

ASSISTANT: Thank you for reaching us.