As the How-To Geek recently explained, you can compare changes in different versions of a PowerPoint deck and automatically accept or reject the changes. Here's what you need to do:
Send a PowerPoint file out for review. After you get back the changed version of the document, open the original and, on the ribbon's Review tab, click Compare. In the resulting file dialog, open the changed version of the file.
You should see the Revision pane on the right side of the screen. The top section -- called Slide changes -- contains each of the proposed changes from the second PowerPoint deck. In other words, this pane highlights anything that's different between the two files. Click each item in turn to accept or reject the change into your original file. The bottom section (presentation changes) points out any added or deleted slides.
When you're done, save the file. All of the changes will be incorporated in the original file. You can throw away the second file; you don't need it anymore.
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