You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: Can you please help me to book a ticket from IAD to LAS?

ASSISTANT: Sure. Let me know your travel dates.

USER: My travelling dates will be on June 17 to June 19.

ASSISTANT: Can I know your name?

USER: Sarah Robinson here.

ASSISTANT: Do you have any preference?

USER: No.

ASSISTANT: Connecting flight can be booked with airline Spirit for price 100 having flight number 1016.

USER: You can proceed to booking.

ASSISTANT: Ticket is booked.

USER: Thank you for your help.

ASSISTANT: Thank you.