How to disable technician that deported without remove history and worklogs

How to disable technician that deported without remove history and worklogs

Hi,
Some technicians in my organization after one or two years deported or dismissed. When I delete technicians, all requests that assigned to this technician move to unassigned. It's very bad.

How to disable these technicians that deported without remove their request history and worklogs?
What should I do?
Do you have any workaround?

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