In Ticket Template - limit Contact Name to Agent who is logged in

In Ticket Template - limit Contact Name to Agent who is logged in

We want to limit the Contact Name field to the name of the Agent who is creating the ticket (the agent who is logged in). We have had issues with Agents opening tickets under other Agent's names and we'd like to create this restriction to solve that problem.  Presently it is a drop down field with all of the agents listed.