I called Microsoft again for a 3rd time this morning and they insist that I must purchase a new Windows 10 license. I already own a Windows 10 Home License so that is ridiculous.
Thanks for nothing Parallels and Microsoft! You put your customers in the middle of an impossible game to win with each blaming the other and neither supplying a proper resolution. The one interesting fact that Parallels did help me with was insisting that the Parallels VM version of Windows 10 be authenticated prior to the Boot Camp version (Which is impossible to do as the Boot Camp version must be installed first).
Since Parallels and Microsoft offered terrible customer service in this regard, I researched and found the following permanent solution. This solution disassociates the Product Key with the Boot Camp version of Windows 10, then validates an active Windows Product Key in Parallels VM, followed by reintroducing activation in the Boot Camp version. I wish I could have my 12 hours back...
1.) Log on to the Boot Camp version of Windows 10
2.) Run 'Command Prompt' as Administrator (Type 'Command Prompt' in the Windows Search Box in the lower-left, then right-click and select 'Run as Administrator')
3.) Enter the following command: 'slmgr -upk <Your Product Key>' (To be safe, I also entered the following command 'slmgr -upk')
4.) Shut down Windows 10 via Boot Camp and reboot into Mac OS (Hold Option Key at boot to select)
5.) Run Parallels Desktop 13 and start Windows 10
6.) Run 'Command Prompt' as Administrator (Type 'Command Prompt' in the Windows Search Box in the lower-left, then right-click and select 'Run as Administrator')
7.) Enter the following command: 'slmgr -upk <Your Product Key>' (To be safe, I also entered the following command 'slmgr -upk')
8.) Reboot Windows 10 via Parallels Desktop 13
9.) Run 'Command Prompt' as Administrator (Type 'Command Prompt' in the Windows Search Box in the lower-left, then right-click and select 'Run as Administrator')
10.) Enter the following command: 'slui 4'
11.) Follow the on screen directions to activate your copy of Windows 10 using Parallels VM (I dialed the supplied phone number and activated successfully)
12.) Shut down and log on to the Boot Camp version of Windows 10 (Notice that you are now activated in both the Boot Camp and Parallels VM versions of Windows)