How can I filter inactive/disable agent tickets?

How can I filter inactive/disable agent tickets?

Hello,

We have an user-agent that left the company and we inactive/disabled his agent. So, now I can no longer filter or search tickets that he is the current owner, or even create a rule to reassign tickets to another person when the ticket is reopen.

Is there a way that I can still filter/search and create rules based on the Ticket Owner where the agent is currently inactive/disabled?