csrutil disable
Restart computer
In the terminal, type
sudo open /Applications/TextEdit.app /System/Library/LaunchDaemons/com.apple.ManagedClient.enroll.plist
change
<key>com.apple.ManagedClient.enroll</key>
<true/>
to
<key>com.apple.ManagedClient.enroll</key>
<false/>
So that the changes take effect
Look back up at what ejm201 had to say on August 12. I was able to reinstall using this method. As far as connecting to the internet, I guess it would depend on how your system is set up. I never used Wi-Fi and just plugged in to ethernet to install. Then I just disconnected from ethernet when I ran initial setup I checked the box saying I don't connect to internet. Before connecting to the internet I followed the instructions provided by ejm201 following his link "in the gist". The only problem I have discovered using this method is that I cannot activate a phone or iPad with the Mac that I am using. Not sure which line is blocking me but it is a small price to pay since my old company refuses to remove Management from the computer that I paid for.