You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I am planning to book a ticket from DCA to AUS. Can you please help me out to book a ticket for me?

ASSISTANT: Sure, please help me with your travelling dates?

USER: I would like to travel on Aug 17 and return back on Aug 19.

ASSISTANT: Is there any connection limit?

USER: Yes, I am looking for a connecting flight.

ASSISTANT: Do you have any class preference?

USER: No, My return back on Evening.

ASSISTANT: Can you share your name please?

USER: My name is Paul Allen.

ASSISTANT: Sorry, there is no flights found with your required dates to travel.

USER: That's fine, thank you for your service.

ASSISTANT: Thank you for opting us.