You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello. How can I aid you?

USER: I need a ticket from Las Vegas, NV-LAS to Washington DC-DCA.

ASSISTANT: Sure, I  can help you. Please share me your travelling dates.

USER: Departure date is 10/26 and 10/28 is my return date.

ASSISTANT: Do you need any connecting flight?

USER: I need direct flight.

ASSISTANT: May I know your name?

USER: I am Emily Young.

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

USER: Thanks.

ASSISTANT: Thank you for choosing us.