Try:
Public Sub PageSize()
' This routine will change the paper size
Debug.Print ActivePage.Shapes("thePage"

.Cells("PageWidth"

Debug.Print ActivePage.Shapes("thePage"

.Cells("PageHeight"
ActivePage.Shapes("thePage"

.Cells("PageWidth"

.Formula = 7.5
ActivePage.Shapes("thePage"

.Cells("PageHeight"

.Formula = 15
Debug.Print ActivePage.Shapes("thePage"

.Cells("PageWidth"

Debug.Print ActivePage.Shapes("thePage"

.Cells("PageHeight"
ActivePage.Shapes("thePage"

.Cells("PageWidth"

.Formula = 8.5
ActivePage.Shapes("thePage"

.Cells("PageHeight"

.Formula = 11
Debug.Print ActivePage.Shapes("thePage"

.Cells("PageWidth"

Debug.Print ActivePage.Shapes("thePage"

.Cells("PageHeight"
End Sub
John... Visio MVP