Hello. I am Robert  Collins.
user
Hello, how may I help you?
assistant
I need to book a flight ticket from LAX to DEN, Can you please help me for booking?
user
Sure, may I know your trip dates please?
assistant
I would like to travel on 05/11 to travel on 05/13.
user
Please wait for a while.
assistant
Sure.
user
Sorry, we regret to inform you that there is no flight available as per your request.
assistant
Ok, no problem. Thanks for your information.
user
Most welcome.
assistant