Is there any way to make a trigger or condition wherein an Agent replies to a New Ticket by a New End User have an automated tag of the Agent's name in their user level? 
So far, I can only figure out is to put an automatic tagging in the specific ticket once the agent has replied on it. I'm trying to have the specific End User be only assigned with only one agent so having their tag in the End User Level makes it work.
Thank you for the help!