Open an OpenDocument Presentation file in PowerPoint
- Microsoft PowerPoint 2010
 
- Click the File tab.
 - Click Open.
 - In the File of type list, click OpenDocument Presentation.
 - Click the file you want to open, and then click Open.
 
- Microsoft PowerPoint 2007
 
- Click the Microsoft Office Button
 , and then click Open. - In the File of type list, click OpenDocument Presentation.
 - Click the file you want to open, and then click Open.
 
Save a PowerPoint presentation in the OpenDocument Presentation format
If you want to switch your default file format to or from ODF or OpenXML (or other formats) , do the following: 
- Microsoft PowerPoint 2010 
 
- Click the File tab.
 
- Under Help, click Options.
 - Click Save, and then under Save presentations, in the Save files in this format list, click the file format that you want to use by default.
 
- Microsoft PowerPoint 2007
 
- Click the Microsoft Office Button
 , and click Save As. - Click OpenDocument Presentation.
 
Important   If you want to keep a PowerPoint version of your file you must first save the file as a PowerPoint document, for example in the .pptx file format, and then save it again in the OpenDocument Presentation (.odp) format.