How to restrict download options on a single report in SSRS

foreach (RenderingExtension extension in this.reportViewer.LocalReport.ListRenderingExtensions()) {
if (extension.Name == "PDF") {
((Extension)(extension.GetType().GetField("m_serverExtension", System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance).GetValue(extension))).Visible = false;
}