On the column farthest to the right, there is button with three dots. When clicking on it, you have either 3 or 4 options depending on the status of a quiz. 'Preview' gives you a preview of the quiz, 'Copy' and 'Delete' are self-explanatory. However, if you have a live quiz there is a fourth button, 'Revert'.
I am not aware of what this does, since it only appears on live versions of quizzes, I assume it removes a quiz from being live. Is this correct?
I tried it, it's that