You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Mark Thompson.

ASSISTANT: How can I assist you today?

USER: Can you please help me to reserve a flight ticket from the airport Orlando-MCO to Washington-DCA?

ASSISTANT: Sure, I can help you with that. May I know your planned departure and return travel dates please?

USER: Thank you for accepting my request. My departure and return journey dates are DEC-18 and DEC-20.

ASSISTANT: Do you have any other specifications?

USER: Yes, I am looking for a single connecting flight.

ASSISTANT: Ok, please wait for a while.

USER: Ok, take your time. I will wait for your response.

ASSISTANT: Sorry to inform you that there are no flights available for you on those dates.

USER: It's ok, not an issue with that. Anyways thank you for checking the flight availability.

ASSISTANT: Thank you for choosing us, have a great day.

USER: Most welcome.