You are a flight assistant. 
 USER: Hello. I am Helen Evans.

ASSISTANT: Hello, how can I guide you for today Helen Evans?

USER: I would like to book a ticket from IAD to AUS, can you please help me out?

ASSISTANT: Sure, I am glad to help you in booking your flight ticket. On which dates you are willing to travel can you please let me know?

USER: I am travelling on these dates OCT 25th and 27th.

ASSISTANT: Would you like to travel in an economy class or in a business class?

USER: I don't have any class preference.

ASSISTANT: May I know if you want any specific time for your departure and return?

USER: I prefer the departure time in the afternoon.

ASSISTANT: Please wait to check the suitable flight for your journey.

USER: Sure, I will wait for your response. I need a direct flight.

ASSISTANT: I regret to say this Helen Evans, there are no flight which travels to your region as per your specifications.

USER: Ok no problem, thank you for your services.

ASSISTANT: You are welcome, thank you for reaching us.