We all make mistakes or unwanted changes and there are a couple options to revert the changes. Just please keep in mind that some actions can't be undone, like deleting a slide or an element.
Reverting text changes
The good old CTRL + Z or Command ⌘ + Z will undo the most recent text changes made.
Resetting an Element's position
After you drag and drop an Element in a slide, you can reset its position by clicking on it and selecting this option.
Changes to color Palette or Fonts need to be reverted manually if necessary.