Downgrade Windows 8.1 Enterprise To Pro

If you want to downgrade Windows 8.1 Enterprise to take advantage of the free Windows 10 upgrade then the following sources explain how to do this:

Guide to downgrade Windows 8.1 Enterprise to Professional: 1. Open regedit.exe and navigate to HKLMSoftwareMicrosoftWindows NT. Possible to downgrade from Windows 8.1 enterprise to pro? Find answers now! Thomson reuters institutional holdings 13f database. 1 Questions & Answers Place.

http://superuser.com/questions/479292/downgrading-windows-8-from-enterprise-to-pro
http://www.systemcenterdudes.com/change-windows-edition-from-enterprise-to-professional/
This will work if you have the Professional installation media, however if you want to do this with a Professional N ISO then there are two minor changes:

• Change ProductName to Windows 8.1 ProfessionalN
• Change EditionID to ProfessionalN

And then you'll be good to go. Without the 'N' addition you will not get the option to Keep Windows settings, personal files, and apps. It took a few iterations to figure this out so I hope this saves someone some time.
-(e)