You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you for today?

USER: I am Ryan Carter.

ASSISTANT: Ok.

USER: I want to book a ticket from DFW to DEN, there is a Entrepreneurship Summit at Denver, shall you please help me for reservation?

ASSISTANT: Sure, I will help you with that. May I know the travelling dates?

USER: My departure day is 10/14 and return day is 10/16.

ASSISTANT: Ok, please wait for a moment.

USER: Ok.

ASSISTANT: Thank you for waiting Ryan. Sorry for the inconvenience, there are no flight found on your requirements.

USER: It's ok. Thank you for your service.

ASSISTANT: Thank you for choosing us, have a great day.