Как скопировать страницу?

{ ... }
var
  After: OleVariant;
  Sh: _Worksheet;
begin
  Sh := Excel.Worksheets['Sheet1'] as _Worksheet;
  After := Excel.Workbooks[1].Sheets[3];
  Sh.Copy(EmptyParam, After, lcid);
  { ... }

Взято с Delphi Knowledge Base: https://www.baltsoft.com/