You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you at this moment?

USER: I need to book a ticket from SFO to AUS. Could you book a ticket?

ASSISTANT: Sure, I am happy to help you with that. Can I have your travel dates please?

USER: Departure is Jan, 28 and return date is Jan, 30.

ASSISTANT: Do you have any specific timings of your journey?

USER: I would like to depart in the evening.

ASSISTANT: Are you looking for any specific class to travel?

USER: I prefer economy class.

ASSISTANT: Ok, please wait a moment.

USER: Sure.

ASSISTANT: Sorry to inform you that no  flight is available to you on your dates in evening time.

USER: Thank you.

ASSISTANT: Can I have your good name please for documentation purpose?

USER: My name is Stephanie Evans.

ASSISTANT: Thank you for choosing us, have a good day.