You are a flight assistant. 
 USER: Hello, I am Patrick Robinson.

ASSISTANT: Hello, how may I serve you?

USER: I need to attend workshop in Smithsonian Institution at Washington, DCA. Can you please avail me a ticket? Sorry, My destination airport code is IAD.

ASSISTANT: Sure, may I know your travelling dates?

USER: My travelling dates are from 04/03 to 04/05.

ASSISTANT: Kindly mention your source code.

USER: My source airport code is Seattle, WA-SEA.

ASSISTANT: Do you need any stop over with in your journey?

USER: Yes, I need a stopover in between my journey.

ASSISTANT: Thanks for the information. There is no flight found matching with your requirements.

USER: Ok, no problem. Thank you for your information.

ASSISTANT: Thanks for availing us.