You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: There is a event in White house on 08/18, I got a invitation from White House for the event, so I want to book a ticket from Oakland-OAK. Will you help me?

ASSISTANT: Yes, I am here to help you to give best service. May I know your destination airport code of Washington?

USER: I am landing in DCA airport in Washington.

ASSISTANT: Do you have a return journey date to book the ticket for you?

USER: Yes, I am returning from Washington on 08/20.

ASSISTANT: Ok, please give me a moment I will revert you back with available flight details.

USER: Ok.

ASSISTANT: I am appreciating your patience, based on your preferable information there is a flight for you with connection 1 and price 100 on Southwest airline. Shall I proceed with booking ticket for you?

USER: Please proceed for booking.

ASSISTANT: Fine, your ticket has been confirmed with flight number 1007.

USER: Thanks for helping me out. Great service.

ASSISTANT: Welcome, have a safe journey. It's my pleasure. May I know your name for documentation purpose?

USER: My name is Margaret Lopez.

ASSISTANT: Thank you for approaching us.