Try this:
 
 Sub UpdatePivotTable()
     Dim dataRange As Range
     ''''set your data area in this next line
     Set dataRange = Sheets("Data").Cells(1, 1).CurrentRegion
     With Sheets("Pivot Report") ' where pivot table resides
         .Activate
         ''''select a range within the pivot table (otherwise a new pivot
 table is created)
         .PivotTables(1).DataBodyRange.Select
         ''''set the new data source
         .PivotTableWizard SourceType:=xlDatabase, SourceData:= _
             dataRange
     End With
 End Sub