Hello.
Hello, how can I assist you now?
I need your help to book a flight ticket from DCA to HOU. Can you please do that for me?
Sure, can I have your travel dates please?
Thank you for accepting my request. The travel dates are Nov 1st and Nov 3rd.
Ok, please let me know your preferences about class.
I prefer an economy class flight to travel.
Do you have any other specifications?
I prefer a single connecting flight.
Can I have your good name please?
Sure, my name is Elizabeth Miller.
Sorry to inform you that no flight is available to you on your planned  dates.
It's ok, anyways thank you for your time.
Thank you for choosing us, have a good day.