Sub Macro1()
Dim Source As Workbook
ThisWorkbook.Sheets(1).Range(Cells(2, "A"), Cells(Rows.Count, "K").End(xlUp)).Copy
Set Source = Workbooks.Open(ThisWorkbook.Path & "\Modifica.xlsx")
Source.Sheets(1).Cells(Source.Sheets(1).Rows.Count, 1).End(xlUp)(2).PasteSpecial xlValues
Source.Close False
End Sub