The plugin "Revoke consent" adds the missing feature to revoke the consent of the privacy policy in moodle.
It can handle the in 3.5 introduced tool_policy and as well the legacy policy implementation.
If the plugin is installed the user will find a new link in his profil to revoke the consent.

Important note: This plugin should only be used in Moodle 3.5! Later versions of Moodle already have the possibility to revoke a consent. Probably it won't work there.

Installation:
Copy all files into the folder "local/revoke_consent" inside your moodle installation.
Run the installation process in moodle.
You can find more detailes to the installation process here: https://docs.moodle.org/35/en/Installing_plugins#Installing_a_plugin