Hello, this is Emily.
Yes, retail key can be transferred.
Some additional things to considered though:
If the Pro is the upgrade license only instead of the full copy of Pro license, you can only transfer it to an already activated Home edition.
If your license was purchased via third party and it was used as an actual product key (25 digits), you need to deactivate it first on the old before you can transfer to the new.
If it is a digital license, purchased from Msft, you don't need to deactivate, in fact, you do NOT want to deactivate first. On the new, do a transfer. go to Settings > System > Activation, run the troubleshooter, choose the hardware change option. When it asks you where it is installed on right now, you should choose the old device name. Then click on Activate button. And on the next screen when it asks you where to transfer it to, choose your new device name.