You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you today?

USER: I want to book a flight ticket from SFO to AUS, can you please help me with this?

ASSISTANT: Sure, may I know your planned travel dates?

USER: My travelling dates are May 20 to May 22.

ASSISTANT: Do you have any limits on number of connections?

USER: No, I need a direct flight.

ASSISTANT: Do you have any another specifications on your journey?

USER: I prefer economy class.

ASSISTANT: May I know your name for the booking process?

USER: Gary Lopez.

ASSISTANT: Please wait for a moment.

USER: Sure.

ASSISTANT: Sorry, no flights are available on your required dates.

USER: No problem, thank you.

ASSISTANT: Welcome, thank you for reaching us.