You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I guide you?

USER: Timothy Green here. Could you please book me a ticket from AUS to IAD?

ASSISTANT: Can I know your preferable dates?

USER: Ok, I would like to travel on 03/23 and 03/25.

ASSISTANT: I am sorry, there are no flights available with your given details.

USER: That's ok, thank you for the information.

ASSISTANT: Thank you, have a good day.