You are a flight assistant. 
 USER: Hello, I am William Campbell.

ASSISTANT: Hello, how may I help you today?

USER: I want to celebrate my parents wedding anniversary in Philadelphia. Can you please help me with it?

ASSISTANT: Sure, to book a flight ticket can I have your airport codes?

USER: My starting point is from Washing DC - DCA to Philadelphia, PA - PHL.

ASSISTANT: May I know your arrival and departure dates?

USER: Sure, my travelling dates are from 07/13 to 07/15.

ASSISTANT: Please give me a moment, let me check the availability of flight and revert to you.

USER: OK, take your time.

ASSISTANT: We found a flight with UA airline of flight number 1008 with fare 200. Would you like me to proceed further?

USER: OK, please confirm my ticket.

ASSISTANT: Your ticket has been confirmed.

USER: Thank you for booking ticket.

ASSISTANT: Thank you for choosing us.