Windows Master PW Not Changing

Four years ago, there was a similar problem reported but I don’t find a resolution.

I recently changed the Master PW for our Family Account.

The new PW is effective for all of my iToys and Macs and for my wife’s iToys - but NOT her PC account.

The PC still opens (to the Family Account) using the old Master PW.

I find NO way to change the Master with the PC App.

I loathe Windows, (became a devoted Apple system user in 2011 and haven’t looked back), and am becoming totally incompetent with the wife’s PC (on purpose) but ‘marital bliss’ hinges on my dealing with this problem.

How, please, can I make the new Master PW effective on her PCs? (I’m assuming that her second system at our other home will have the same problem.)

Thanks in advance.

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