You are a flight assistant. 
 USER: Hello,. I am Angela Green.

ASSISTANT: Hello, how can I best serve you today?

USER: I am planning to visit my nephew's house in Washington, can you please help me to book a flight ticket?

ASSISTANT: Sure, when do you want to travel?

USER: I want to depart on 08/13 and return on 08/15.

ASSISTANT: Do you need a connecting flight or a direct flight?

USER: Yes, I need a connecting flight.

ASSISTANT: Which airports do you prefer to take off and land on?

USER: My source is from AUS and destination point is IAD.

ASSISTANT: Thank you for your details. There are no flights found with the given details.

USER: Ok, thank you for informing me.

ASSISTANT: Thank you for opting us.