ReportParameter p1 = new ReportParameter("param1", _p1);
ReportViewer1.LocalReport.SetParameters(new ReportParameter[] { p1 });

Off the top of my head:

declare p1 = new ReportParameter("param1", _p1)
invoke ReportViewer1::LocalReport::SetParameters( table of ReportParameter (p1) )

I can't swear to that - it's still early in the morning for me and I drove 1300 miles over the weekend, so I may not be at my best. Also, I assume we're talking about a recent version of COBOL for .NET. (Please include product, version, and platform information in every question.)

ReportParameter p1 = new ReportParameter("param1", _p1);
ReportViewer1.LocalReport.SetParameters(new ReportParameter[] { p1 });

It would look something like the following:

      $set ilusing"Microsoft.Reporting.WinForms"
     
           declare p1 as type ReportParameter = new ReportParameter("param1", _p1)
           invoke ReportViewer1::LocalReport::SetParameters(table of type ReportParameter(p1))