Hi.
user
Hello, how may I assist you?
assistant
My name is Deborah Turner. I want to book a ticket  to attend a meeting in DCA from IAH, please can you help me to book a ticket?
user
Yes, sure. Could you let me know your travel dates?
assistant
My travelling dates are 02/21 to 02/23.
user
Sorry, Deborah Turner there is no flight on your preferable dates. Thank you for choosing your service.
assistant
It's ok.
user
Bye.
assistant
Thank you for providing  the information.
user
Your welcome.
assistant