Downgrading installed Win10Pro to Home Prem?

About a year ago I took advantage of MS’s “Free Win7 to Win10 upgrade” plan and got a Windows 10 Pro product licence that is on my current PC (an AMD Phenom 955 build).

I was given a copy of Win10 Home Prem Retail by a family member who bought out from an unscrupulous pc tech when their very old laptop had a virus, and Win10 wouldn’t run because it was below system specs.

Now I am building a new Ryzen 1700x system this week. I would like to use the Win10 Pro license on the new build and the win 10 home premium on the older build.

Is there a way to do this without reformat/reinstall the older pc and entering the Home Prem credentials during install? There are some music production tools on that pc which I no longer have the installation disks for.

Also, I have never swapped windows licences between hardware before (always had a fresh windows per pc), what is the process/pitfalls etc do I need to watch out for, I know that the licences are tied in some way to your hardware.

Thanks in advance!

If you want to tie it with a Microsoft account you can try that for the pro key then deactivate the old build.

Alternatively you can try contacting Microsoft’s support line and tell them that you need to transfer a key.

This is with Windows 7, but looking it up might be useful for research

I’m not sure if this works for downgrading but worth a try.
Run>changepk.exe>enter Home product key.

Edit: BTW there’s no such thing as Win 10 Home premium. There’s only Home or Pro(including S) for consumers. It’s worth checking out if you actually need Win 10 Pro as well.

I know the big use for my current rig is remote desktop.

I know many other remote technologies exist (I use VNC with my multiple RaspPi’s.

I suppose Home covers my needs as long as Home does powershell, Windows under Linux and a few other things that formerly were packaged as MS Power Tools which I believe were only available to Professional editions of XP/Vista/7/8.

Either way let me know if the downgrade works as I would find it useful too.

Still a day or two away from getting my hardware, but for other people in similar quandaries, if you are interested in options such as the Windows Linux Subsystem (basically having a linux distro running inside Windows 10, want bash and linux tools in Win10 vs a traditional VM?) you will need the Pro edition for its Hyper-V technology (a tier-1 virtualization, vs tier 2 like virtualbox… I’m not personally sure much of the difference as I don’t do much with VM’s, but the distinction seems important to visualization technology).