You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I serve you?

USER: I would like to book a ticket to Washington to attend a business meeting, can you please aid me in booking?

ASSISTANT: Sure. When would you like to travel?

USER: I would like to travel on 01/18 and recur on 01/20.

ASSISTANT: Do you need any stopover?

USER: No, I need a direct flight.

ASSISTANT: Can I know your name?

USER: I am Matthew Rodriguez.

ASSISTANT: Please share me your nearest airport codes.

USER: My boarding is at Denver, CO-DEN and landing is at DC-DCA.

ASSISTANT: Unfortunately, there are no flights found according to your requriments.

USER: OK, no issues. Thank you.

ASSISTANT: Thank you for choosing us.