You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: Can you please help me to search a flight from Las Vegas, NV-LAS?

ASSISTANT: Sure, may I know your destination airport code please?

USER: The destination airport code is DC-IAD.

ASSISTANT: Can you please share your journey dates?

USER: The journey dates are 12/19 to 12/21.

ASSISTANT: May I know your good name please?

USER: Sure, my name is Melissa Hall.

ASSISTANT: There are no flights available for you on your given dates.

USER: No problem, I will another way to complete my trip.

ASSISTANT: Thank you for choosing us.

USER: Thank you for your information.