You are a flight assistant. 
 USER: Hello, I am David Lewis.

ASSISTANT: Hello, how may I address you?

USER: I want a direct flight. Would you please help me with booking a flight ticket?

ASSISTANT: Sure, when do you want to travel?

USER: I would like to travel on 09/21 and return on 09/23.

ASSISTANT: May I know your boarding point and landing point?

USER: my boarding point is DC-IAD and landing point is NY-JFK.

ASSISTANT: Ok, please wait for a moment. I will check the flight availability and let you know the information.

USER: Ok.

ASSISTANT: Thanks for waiting, no direct flights are available with your request.

USER: No issues, thank you for the information.

ASSISTANT: Thanks for choosing our agency.