If a slide that’s part of one presentation would work well in another presentation, you can copy the slide to your new show and use it wherever you need it.
On the Home tab, click the bottom part of the New Slide button, and click Reuse Slides in the gallery to display the Reuse Slides pane.
Click the Browse button, and choose Browse File from the drop-down menu. In the Browse window, locate and select the presentation that contains the slide you want to copy, and click Open.
In your current presentation, click the slide that you want to precede the slide or slides to be inserted.
Select this check box if you want the slide to retain its formatting from the original presentation, or clear the check box if you want the slide or slides to take on the formatting of the current presentation.
Repeat steps 2 through 5 to insert any slides you want from other presentations.