You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you today?

USER: I am Jeffrey Turner, I would like to attend Global Environmental Conference in Benaroya hall, which is at Seattle, WA-SEA. Could you please help me with booking a flight ticket from DC-DCA?

ASSISTANT: Sure, can I know your source code? Ok, may I know your price limit?

USER: I can afford up to 500.

ASSISTANT: Ok, can I know your travelling dates?

USER: I intend to board on 01/23 and return on 01/25.

ASSISTANT: We found a flight of Delta airline, flight number 1000 with the fare of 300.

USER: Yes, please proceed with booking.

ASSISTANT: Your ticket has been booked.

USER: Thank you for your assistance.