Hi.
user
Hello.
assistant
I am Richard Scott.
user
How may I help you today?
assistant
  I am very excited as this trip is very special, I am going to hangout with my school friends after a long time.Can you please book a ticket from DCA to IAH? My travelling dates are 04/23 to 04/25.
user
Ok, please wait a moment.
assistant
Take your time.
user
Sorry Scott, there are no flights had been found on your details.
assistant
Sorry, there is no flight available.
user
Thank you for reaching us.Have a nice day.
assistant