Removing or pausing a widget
The short answer
To remove a widget from a page, delete the embed code from that page. To switch it off everywhere at once without touching your site, hide it from the dashboard.
Hiding is reversible and instant; deleting the code means re-pasting it later.
Removing it from one page
Delete the embed code from that page or block. Clear your site cache afterwards, or the widget appears to still be there.
Switching it off everywhere
Use the hide option in the dashboard. The widget stops rendering on every site the code is on, and the console will show WIDGET_NOT_FOUND. Unhide and it returns, with no changes to your site.
The other route is commenting the code out, which keeps it in the page for later without rendering.
Deleting it permanently
Deleting the widget in the dashboard removes its configuration. Any manually added reviews go with it — reviews collected from platforms are unaffected, since those live on the platforms.