Hi.
Hello.
I am Mark Campbell.
 How can I help you now?
I want to book a ticket from LAS to DEN, can you help me?
Sure, we are here to help you, can you please  share your travelling dates?
My travel dates are 05/19 and 05/21.
Please wait a moment.
Sure.
Sorry Mark Campbell, there is no flight found as per your travelling dates.
No problem, thanks for checking.
Thank your for reaching us.