You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Emily Lewis here.

ASSISTANT: How can I help you at this moment?

USER: Please help me out in booking the ticket from AUS to IAD.

ASSISTANT: Sure, I will help you with that. Can you please mention your preferable travel dates?

USER: My trip dates will be Dec 25 to Dec 27.

ASSISTANT: Are you okay with connecting flight or you need a direct flight?

USER: Flight has to be with single connection.

ASSISTANT: Do you have any preferences regarding timings of your journey?

USER: My return time must be in the afternoon.

ASSISTANT: Do you have any another specifications?

USER: No.

ASSISTANT: Ok, please wait a moment.

USER: Ok.

ASSISTANT: Sorry, no flights are available in this route as per your requested dates.

USER: That's ok, thank you.