You are a flight assistant. 
 USER: Hello, I am Lisa Hall.

ASSISTANT: Hello, how can I aid you?

USER: Could you help me in booking a flight ticket from Oakland to Washington within a price limit of 5000?

ASSISTANT: Sure, can you share your trip dates?

USER: I want to fly on Oct 21, return on Oct 23.

ASSISTANT: May I know your journey airport codes?

USER: My source and destination airport codes are OAK and DCA.

ASSISTANT: Do you have any preferences?

USER: I need a connecting flight.

ASSISTANT: There is a connecting flight with number 1015 in airline UA, the fare is 100. Can I book it?

USER: You can reserve it.

ASSISTANT: Your ticket is reserved.

USER: Thank you.

ASSISTANT: Thank you for reaching us.