Keynote
Undo or redo changes in Keynote on Mac
You can undo recent changes then redo them if you want them back.
Undo or redo actions
Go to the Keynote app
on your Mac.Open a presentation, make any edits, then do one of the following, as necessary:
Undo the last action: Choose Edit > Undo (from the Edit menu at the top of your screen), or press Command-Z on your keyboard.
Redo the last action you undid: Choose Edit > Redo, or press Shift-Command-Z.
If you want to delete all the changes you made since you opened a presentation, you can restore the presentation to its state when you opened it.