Duplicate slides within a presentation
To add a slide that contains the content of an existing slide in a presentation, you can duplicate the slide.
In the pane that contains the Outline and Slides tabs, click the Slides tab.
Select one or more slides that you want to duplicate. To select multiple slides, click a slide, and then press and hold CTRL while you click the other slides.
On the Home tab, in the Slides group, click the arrow next to New Slide, and then click Duplicate Selected Slides.
Note The duplicated slides are inserted directly underneath the lowermost slide that you selected.