If you have made some changes to a file and you need to revert it to previous versions you can do this in One Drive on Office 365.
- Click on the menu button next to the file you want to recover.
- Select Version History from the Menu.
- This will give you a list of the previous versions of the file, select the menu button next to the version you want to restore the file to and click restore from the menu.
- Your file will now revert to that version, if it's not the version you want you can do it again and restore an even earlier version.