You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I assist you for today?

USER: Can you help me to book a economy class flight?

ASSISTANT: I am happy to help you about that. Can you please provide your planned dates of journey?

USER: I would like to travel on Mar 19 and 21.

ASSISTANT: May I know your source airport code of your journey?

USER: Sure, please book a flight from SFO at evening flight.

ASSISTANT: Can you please let me know your destination airport code of journey?

USER: Please book a return ticket from AUS at morning time.

ASSISTANT: Would you prefer to have a connecting or a direct flight for this trip?

USER: I prefer connecting flight.

ASSISTANT: Is there any other specifications for your journey?

USER: No.

ASSISTANT: Please provide your name for booking purpose.

USER: My name is Elizabeth Harris.

ASSISTANT: Sorry to say this Elizabeth Harris, there are no flights which travels to your region on your planned dates of journey.

USER: No issues, thank you for your time.

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