Do you want to display slides in both Portrait & Landscape direction or orientation mode is same PowerPoint presentation simultaneously? By default slideshow layout is in landscape orientation and you can switch the whole slideshow to Portrait orientation. There is a workaround, where you can use both orientation modes in same slideshow.
Use Portrait & Landscape modes simultaneously
To achieve this, you need 2 presentation slideshow files. You can link these cleverly, so that for viewer it appears as one presentation with alternating orientation modes.
1. Create two separate PowerPoint presentation files each with different Portrait & Landscape mode.
2. Save both these files in same folder location. Even when you move this folder to different drive or CD, links won’t break.
3. In the first presentation on specific slide select text, object or element and link to second presentation. For this, click Action on Insert tab in Links group.
4. Select either Mouse Click tab or Mouse Over tab, click Hyperlink to select Other PowerPoint Presentation from the list.
Similarly, you can create hyperlink on specific slide of second presentation to go back to first presentation. So, during live presentation, slides with different orientation from two PowerPoint files will appear as one comprehensive slideshow for users.