OLC - Adding Non Worker as Manager to track learning of his direct reportees who is Non Worker

Summary:

We need to have Non-Worker Managers to be able to see their Non Worker staff on what learnings they have completed and assign courses (just like an internal manager has).

But when we opened one of the Non Worker and tried adding him the Non Worker manager, we are unable to search for Non-worker Manager under My Client groups>Person Management> Search for Non worker> Click on Actions drop down and select Correct/Update> Under Manager details field, tried searching for Non worker to add him as a Manager for another Non worker. But unable to search for this Non worker.