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

ASSISTANT: Hello, how may I help you at this moment?

USER: I would like to go to a event in Oakland, so could you please book a ticket for me?

ASSISTANT: Sure, I will help you. Please send your travelling dates.

USER: Sure, I would like to go on 07/28 and return back on 07/30.

ASSISTANT: Can I have your nearby airport codes please?

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

ASSISTANT: Please wait for a while.

USER: Ok, ensure it is a single connecting flight.

ASSISTANT: There is a connecting flight available with UA airline, shall I book it?

USER: Ok, please proceed for further if it costs you below 200.

ASSISTANT: Your booking is done with flight number 1009. Happy journey.

USER: Thank you for booking.

ASSISTANT: You are welcome, have a nice day.