The Undo feature in Word has saved many a document. It’s wonderful because you can step back a series of operations, but you cannot select from this list of actions.
An alternative is to turn on Track Changes from the Review tab. You can also turn on the Reviewing Pane from the same Tracking group. Now you can see a list of the changes you are making, click on a particular change and click on the Reject button to “undo” it. This method gives you a little more flexibility in how you address changes to your document.