You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you today?

USER: I am Margaret Lewis. I want to book a flight ticket from Denver DEN to San Francisco SFO. Can you make reservation for me?

ASSISTANT: Sure, I am here to help you. May I know your travel dates please?

USER: Thank you. My planned trip dates are on May 20 and return on May 22.

ASSISTANT: Ok, hold on for a moment. Let me check the best flight for you.

USER: Sure. take your own time.

ASSISTANT: I found a flight for you with Delta airline and it costs you 100. Shall I proceed?

USER: Yes, you can proceed with the booking.

ASSISTANT: Your ticket has been booked with 1013 flight number. Welcome, thank you for choosing us. Have a safe flight.

USER: Thank you for your service.