You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I support you today?

USER: I am Shirley Rodriguez. I have got an invitation from the president, so I need to go White house for that. Please help me with booking a flight ticket to Washington?

ASSISTANT: Sure, I am here to help you. May I know your landing and boarding airport codes?

USER: My landing is at DC-DCA and boarding is at TX-AUS.

ASSISTANT: Ok, please share your travelling dates?

USER: My travel dates are from 04/20 to 04/22.

ASSISTANT: Do you have any other specifications?

USER: I need a direct flight. Price limit is 200.

ASSISTANT: Ok, please wait for a moment.

USER: Ok.

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

USER: Ok, no problem. Thank you.

ASSISTANT: Thanks for approaching us.