Query: user: I want to book a flight to Sydney, NSW in Australia.
assistant: Sure, where are you departing from and what date?
user: I'm leaving from SD, can you check flights on the 2nd of this month?
assistant: Sure, and when do you want to return?
user: I want to leave on the 12th of this month. Can you book economy?
assistant: Okay I have a united Airlines flight departing at 7:20 am, returning at 10:05 pm. Total cost for the return flight is $305.
user: What airport is that flying out of?
assistant: You'll be departing from SAN International Airport.
user: What airport am I flying into? Is this a refundable ticket?

Intent: Flights:SearchRoundtripFlights