You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Patrick Hill, I want to book a flight ticket to DFW from LAS.

ASSISTANT: Ok, may I know your travelling dates?

USER: Ok, my travelling dates are 09/10 and 09/12.

ASSISTANT: Ok, please wait. Sorry, I did not fine any flight to reserve your ticket in your preferable dates.

USER: Ok. Not an issue, anyway thank you for the information.

ASSISTANT: Most welcome.