Expanding and Collapsing
PowerPoint also makes it easy to hide all the bullets under a slide's title (commonly called collapsing the outline) or display every line (expanding). Collapsing an outline to just the titles lets you see the overall organization and flow of your presentation, without being distracted by details. Expanding allows you to work on all the bullet points, and compare them across slides. Click inside the slide you want to change (or select a number of contiguous slides) and click the Collapse button to hide all the detail, or click Expand to show all the detail.
Note
PowerPoint does not have the capability to expand or collapse to a particular level in the hierarchy: It's an all-or-nothing setting. Either you see all the lines in a slide, or you see just the title.
If you want to collapse or expand all the slides in the presentation in one fell swoop, click the Collapse All or Expand All buttons on the Outlining toolbar.