In a Modal form, how can I make the process follow, without having to close the form?

I have a Modal Form, which shows a reportviewer, I use .ShowDialog, but I want to open n_veces that same form, but I have not been able to do it, someone knows how to continue the process using "ShowDdialog".

public void mostrarFactura()
    {
        try
        {


                 Forms.PDFViewer pdfviewer = new Forms.PDFViewer();

                 pdfviewer.Refresh();
                 pdfviewer.PDFViewer2.Clear();
                 pdfviewer.PDFViewer2.LocalReport.Refresh();

                 pdfviewer.PDFViewer2.LocalReport.ReportPath = path.Combine("C:\Pdf\pdfvisualiza.rdlc");
                 pdfviewer.PDFViewer2.LocalReport.ReportEmbeddedResource = "Factura.RDLC.pdfvisualiza.rdlc";

                 pdfviewer.PDFViewer2.LocalReport.EnableExternalImages = true;
                 pdfviewer.PDFViewer2.SetDisplayMode(DisplayMode.PrintLayout);
                 pdfviewer.PDFViewer2.ProcessingMode = ProcessingMode.Local;

                 pdfviewer.PDFViewer2.LocalReport.SetParameters(lista);
                 pdfviewer.PDFViewer2.LocalReport.DataSources.Clear();
                 pdfviewer.PDFViewer2.LocalReport.DataSources.Add(data);


                 pdfviewer.PDFViewer2.ZoomMode = ZoomMode.PageWidth;
                 pdfviewer.PDFViewer2.RefreshReport();
                 pdfviewer.PDFViewer2.Show();


                 log("Showing pdfviewer");
                 try
                 {
                     pdfviewer.PDFViewer2.LocalReport.Render("Image",deviceInfo);



                     pdfviewer.ShowDialog();
                     cambiaIva = false;

                 }
                 catch (Exception e)
                 {
                     MessageBox.Show(e.Message);
                 }

        }
        catch (Exception e)
        {
            throw new Exception("Error en mostrarPDF:\r\n" + e.Message);
        }
    }