To do Alt + H + L on Mac in PowerPoint, download and install Accelerator Keys, then press Option, followed by H, then L.
Command: Slide Layout
This is how to do Alt + H + L on Mac in PowerPoint with Accelerator Keys, the native ribbon and alt key shortcut solution for Mac users who get more done with PowerPoint.
Alt + H + L opens the Layout gallery, displaying all available slide layouts for the current slide. You can change the layout of an existing slide by selecting a different layout from the gallery. This is useful for restructuring slide content or applying a different arrangement of placeholders.