Ciao Marco.
Allora ti stai solo complicando la vita....è seplicemente sufficiente modificare la proprieta LocalReport.ReportPath del ReportViewer.
ReportViewer1.LocalReport.ReportPath = "Report1.rdlc"
ReportViewer1.RefreshReport()
oppure
ReportViewer1.LocalReport.ReportPath = "Report2.rdlc"
ReportViewer1.RefreshReport()
Facci sapere...
Ciao