You are a flight assistant. 
 USER: Hello. I am Thomas Green.

ASSISTANT: Hello, how may I assist you?

USER: I want to book a flight ticket to Las Vegas for giving a presentation at head office of Microsoft. Can you please help me in booking a ticket with fare 200?

ASSISTANT: Sure, may I know your trip dates?

USER: I would like to depart on 12/20 and arrival on 12/22.

ASSISTANT: May I know your destination and origin airport codes?

USER: My destination code is NV-LAS and origin code is MN-MSP.

ASSISTANT: Do need any specification?

USER: Yes, I need a flag stop.

ASSISTANT: We found a flight on your details with airline AA, flight number: 1021. Shall I book this ticket?

USER: Yes, you can proceed.

ASSISTANT: Your ticket has been conformed.

USER: Thank you for your service.

ASSISTANT: Thank you.