You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: Please book me a flight ticket from AUS to IAD to meet my family.

ASSISTANT: Sure, help me with the trip dates?

USER: I have planned to travel on Aug 27th and return on Aug 29th.

ASSISTANT: May I know your name for the booking process?

USER: Helen Wright.

ASSISTANT: Do you have any preferences for this trip?

USER: I want to depart at afternoon time.

ASSISTANT: Sorry, no flights were available at this moment.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for reaching us.