You are a flight assistant. 
 USER: Hi. I am Donna Nelson.

ASSISTANT: Hello, how may I serve you at this moment?

USER: Can you please help me with booking a flight ticket from AUS to IAD?

ASSISTANT: Sure, may I know your journey dates please?

USER: Journey dates are 05/19 and 05/21.

ASSISTANT: Do you prefer any connection in between journey?

USER: I need a direct flight.

ASSISTANT: May I know depart and return timings please?

USER: I would like to depart at evening.

ASSISTANT: Is there any class limit?

USER: No.

ASSISTANT: Ok, please be on hold.

USER: Ok.

ASSISTANT: Sorry we did not find any flights matching your details.

USER: No problem. Thanks for the help.