How edit pivotfilters in excel pivot table?

[dmitry chov]

using Excel = Microsoft.Office.Interop.Excel;
...
Excel.Application xlApp = new Excel.Application();
Excel.Worksheet xlWorkBook = xlApp.Workbooks.Open(templateFileReport);    
Excel.Worksheet xlWorkSheet = (Excel.Worksheet)xlWorkBook.Worksheets.get_Item(1);
pivotTables = (Microsoft.Office.Interop.Excel.PivotTables)xlWorkSheet.PivotTables(Type.Missing);
Excel.PivotTable table = pivotTables.Item(1);
Excel.PivotField pf=(Excel.PivotField)table.PivotFields("end date");

pf.PivotFilters .Count is 0. Why?
There is filter named 'end date' in pivot table excel report. Filter has some value.

How get exists pivot filter for change it?