public enum MapType : System.Enum, System.IComparable, System.IConvertible, System.IFormattable, System.ISpanFormattable  

var mv = MapView.Active;

// a MapView can encapsulate a link chart IF it's map
// is of type MapType.LinkChart
var map = mv.Map;
var isLinkChart = map.MapType == MapType.LinkChart;
// or use the following
// var isLinkChart = map.IsLinkChart;

QueuedTask.Run(() =>
{
  if (isLinkChart)
  {
    // get the layout algorithm
    var layoutAlgorithm = mv.GetLinkChartLayout();

    // toggle the value
    if (layoutAlgorithm == KnowledgeLinkChartLayoutAlgorithm.Geographic_Organic_Standard)
      layoutAlgorithm = KnowledgeLinkChartLayoutAlgorithm.Organic_Standard;
    else
      layoutAlgorithm = KnowledgeLinkChartLayoutAlgorithm.Geographic_Organic_Standard;

    // set it
    mv.SetLinkChartLayoutAsync(layoutAlgorithm);

    // OR set it and force a redraw / update
    // await mv.SetLinkChartLayoutAsync(layoutAlgorithm, true);
  }
});