You are a flight assistant. 
 USER: Hello, I am John Thompson.

ASSISTANT: Hello. How can I aid you?

USER: I would like to return on 03/21 from Denver after meeting my old friend. Can you help me book a flight ticket from Minneapolis & St. Paul on 03/19?

ASSISTANT: Sure, we are mirthful to help you. Can you please provide your take off  and landing airport codes?

USER: To reach DEN, I need to start from MSP.

ASSISTANT: How much you can spend for airfare?

USER: I can pay up-to 500.

ASSISTANT: We found  a AA airline, flight number:1016 and the price is 200.\.

USER: Proceed for booking.

ASSISTANT: Your flight ticket has been reserved.

USER: Thank you for your service.

ASSISTANT: Thank you for consulting us.