How to save a presentation

var
  EmbedFonts: OleVariant;
begin
  EmbedFonts := False;
  PowerPoint.ActivePresentation.SaveAs('PresName.ppt', ppSaveAsPresentation, EmbedFonts);

The second parameter for SaveAs determines the save format - possible values are ppSaveAsAddIn, ppSaveAsPowerPoint3, ppSaveAsPowerPoint4, ppSaveAsPowerPoint7, ppSaveAsPresentation, ppSaveAsRTF, or ppSaveAsTemplate. These are constants defined in the type library. If you aren't using the type library, you can define them yourself like this:

const
  ppSaveAsPresentation = $00000001;
  ppSaveAsPowerPoint7 = $00000002;
  ppSaveAsPowerPoint4 = $00000003;
  ppSaveAsPowerPoint3 = $00000004;
  ppSaveAsTemplate = $00000005;
  ppSaveAsRTF = $00000006;
  ppSaveAsShow = $00000007;
  ppSaveAsAddIn = $00000008;
  ppSaveAsWizard = $00000009;
  ppSaveAsPowerPoint4FarEast = $0000000A;
  ppSaveAsDefault = $0000000B;