You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: I want to book the flight ticket from AUS to DCA. Can you please help me?

ASSISTANT: Sure. Tell me your travel dates please?

USER: My travel dates are Sept 26 and Sept 28.

ASSISTANT: May I know your name please?

USER: Alexander Gonzalez.

ASSISTANT: Are you looking for a stopover in your journey?

USER: No.

ASSISTANT: Any other preferences?

USER: I would like to return in the evening.

ASSISTANT: Please wait.

USER: Ok.

ASSISTANT: Thanks for waiting. But I am sorry to say that there are no flights available.

USER: Not an issue, thank you for the information.

ASSISTANT: Thank you.