Even if you don’t have PowerPoint 2013, you can open and work with a powerpoint 2013 file. And if you are lucky enough to have the new version, compatibility mode makes it possible to work with the older file formats, too.
Turn on compatibility mode
Open a powerpoint 2013 presentation.
On the File tab, click Save As, and then click Browse.
In the Save as dialog box, in the Save as type list, click powerpoint 97-2003 Presentation (*.ppt).
Note: After you click Save, you might get a compatibility checker alert like the one below, telling you which features might be lost or degraded when saving the presentation in the earlier version.
Open the file in an earlier version of powerpoint.
Turn off compatibility mode
To turn off compatibility mode, simply save the presentation as powerpoint 2013 (.pptx) format.