My intent with the document I’ve created in Adobe Illustrator was to save one as an original and one as a copy with a few different characteristics. Accidentally, I saved both with the changed characteristics. How can I revert one back to the original?
The Revert function in Illustrator takes you back to your last Save.
If you saved over your working copy AND your back-up copy, then the only option is to find an older file that existed before you made the changes.
If you do regular back-ups or use backup software, you’ll have to go back to that.
On the Mac if you have Time Machine running, you can go back and restore a previous version of the file.
If that’s not an option, then you’ll have to re-do the work.