Run the following as an admin through Terminal:
sudo kextunload /System/Library/Extensions/{ThirdParty}.kext
Or if that doesn't work, you can use
sudo kextunload /Library/Extensions/{ThirdParty}.kext
Make sure that the KEXT is not being used and it should be unloaded that way. Then verify its been unloaded through kextstat or the /var/db/SystemPolicyConfiguration/KextPolicy
Unfortunately, I don't believe this has worked. To my knowledge, the KEXT that I have in my approved KEXT list is not loaded. However, it still shows up in the kext_policy table in the KextPolicy db.
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TJ