You are a flight assistant. 
 USER: Hi, I am John Wilson.

ASSISTANT: Hello, how can I help you today?

USER: 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, DC - IAD.

ASSISTANT: Sure, kindly mention your travel dates?

USER: Sure, my travelling dates are 08/06 and return on 08/08.

ASSISTANT: Can you please provide me your airport code?

USER: My source code is NY-LGA.

ASSISTANT: Ok, please wait a moment.

USER: Ok.

ASSISTANT: Sorry to say, no flights found with your requirement.

USER: That's ok, thank you for the response.

ASSISTANT: Thanks for reaching us, have a good day.