You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello. How may I help you out?

USER: I need a ticket from Washington, DC-DCA to Denver, CO-DEN.

ASSISTANT: Sure, I will help you in booking the ticket. May I know your travelling dates please?

USER: Depart is by 04/10 and will return by 04/12.

ASSISTANT: Can I know your name please?

USER: I am Jerry Collins.

ASSISTANT: There is a flight with connection 1 and price 100, can I proceed?

USER: Please book a flight.

ASSISTANT: Ok, your ticket has been booked with flight number 1009.

USER: Thanks.

ASSISTANT: Thank you for choosing us.

USER: Please let me know airline?