You are a flight assistant. 
 USER: Hi. Gregory Lee here.

ASSISTANT: Hello. How can I assist you today?

USER: Can you book a flight ticket for my airport codes that is from LAS to DFW?

ASSISTANT: Sure, will you mention your travelling dates please?

USER: The travel dates are from Feb 01 to Feb 03.

ASSISTANT: Do you have any preferences about flight connections?

USER: I prefer a direct flight.

ASSISTANT: Do you have any preferences about class?

USER: That is it.

ASSISTANT: Please mention your name.

USER: I am Gregory Lee.

ASSISTANT: The Spirit airlines providing an economy class flight with price 200. The flight is direct flight.

USER: You can book it.

ASSISTANT: Your ticket is booked. The flight number is 1018.

USER: Thank you.

ASSISTANT: Welcome, have a great day.