Once you've completed the Rent-to-Own program for Parallels, Splice will email you a copy of the serial number to the email associated with your Splice account.
You would then register for a new Softube account and then verify that new Softube account through the email associated with that Softube account.
Next, register the serial number you got emailed from Splice on Softube's website.
Create your iLok account on Softube's website
Download the Softube Central software
Uninstall the version of Parallels installed through Splice
To uninstall, remove the plugin files from these locations:
AU: Macintosh HD/Library/Audio/Plug-Ins/Components
VST: Macintosh HD/Library/Audio/Plug-Ins/VST
AAX: Macintosh HD/Library/Application Support/Avid/Audio/Plug-Ins/
C: > Program Files > Vstplugins or C: > Program Files > Steinberg > Vstplugins*
C: > Program Files\Common Files\VST3
C: > Program Files\Common Files\Avid\Audio\Plug-Ins
Download and install Parallels directly through Softube Center
Click on the "Activate" button to associate your license with your machine.
At this point you should have a fully unlocked version of Parallels running on your machine.