To disconnect Google Search Console from a website, go to that website's setup page or Edit page and click Switch account next to "Connected as {your email}".
This immediately removes the stored connection and clears the linked property. It does not delete or change any previously completed audit results — those stay exactly as they were. The change only takes effect on your next audit, where the two Search-Console-dependent checks will show as Locked again until you reconnect.
To reconnect (with the same or a different Google account), just go through the connection flow again — Google will always show the consent screen, even if you've connected before.