You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you today?

USER: I am Mark Lee. I want to book a ticket from DCA to LAX to attend seminar, can you help me in booking?

ASSISTANT: If you provide me the travel dates also, it is easy for me to search a flight for you.

USER: I am departing on 05/26 and return on 05/28.

ASSISTANT: There is a direct flight with your travel dates, shall I proceed with this flight?

USER: Please proceed for booking.

ASSISTANT: Your ticket has been booked flight-1023.

USER: Thank you for your help.

ASSISTANT: My pleasure.