Chart.SetDefaultChart (PowerPoint)

Specifies the name of the chart template that Microsoft Word uses when it creates new charts.

SetDefaultChart (Name)

Name: Specifies the name of the default chart template that Word uses when it creates new charts. This name can be set to either the name of a user-defined chart template in the gallery or a special XlChartGallery constant, xlBuiltIn, to specify a built-in chart template.

Dim strName As String: strName = 
ActivePresentation.Slides(1).Shapes(1).Chart.SetDefaultChart Name:=strName