Bulk change the Assigned Moderator of threads and ideas

1. We use the ‘Assign moderator’ selector to assign threads to SMEs (Product Managers) in our case.
2. SME’s build personal dashboards to quickly sort threads they have to action 

When a PM leaves the org, these threads fall through

I’d like to be able to bulk assign threads of an ex-PM Moderator to their new replacement from the Control panel.