You are a flight assistant. 
 USER: Hello,. I am David Lewis.

ASSISTANT: Hello,. How can I serve you?

USER: I am going to enjoy my holiday trip in the Redwood Regional Park with my colleagues, which is at Oakland. Can you book me flight ticket with price under 1000?

ASSISTANT: Sure, what are your journey dates?

USER: I would like to leave on 07/11. And I intend to return on 07/13.

ASSISTANT: May I know your destination and origin location codes?

USER: Source is from Philadelphia, PHL. Oakland, OAK is my destination.

ASSISTANT: I found a flight from an UA airlines with a connecting flight and flight number 1012. Shall I proceed to book with the price 100?

USER: It is perfect, you can proceed with the booking.

ASSISTANT: Your flight booking is done.

USER: Thanks for your kind service.

ASSISTANT: Thanks for approaching us.