Deadlock when changed workflow on existing Tickets/Activites/...

Situation:
You worked for a certain time with an existing workflow and discovered room for optimization.
You changed workflow and removed some status or workflow steps which are in use on the old workflow. And as long you didn't have new workflow in place, you can't change to one of the new status. But having new workflow in place issue below occurs.

Issue:
You can't change status on this items – neither forward nor backward.

Two workarounds/possible solutions:
When you update a used workflow, removing some status, adding others you can manage it
either (especially when you already deleted / reworked old workflow)
1. To make a copy of existing record and start with new status within new workflow.
2. Delete old record.
or
just do it in several steps:
1. add the new status in the workflow
2. move all the records in disepearing status a new possible status
3. remove the old status in the workflow

A third possible way to solve this problem:


As I had a major rework in my workflows, I invented following model and had good experience:


1. I set up a dedicate workflow only for administration user, all other users are disabled -- I named it repair workflow.
2. With this repair workflow adminstration user can set every status value to every other value.
3. In the meantime no other user can change any status. This prevents irritation and sideeffects.
4. Repair workflow could be set immediately to make every change necessary and is set back to normal workflow immediately as well.