Public Sub ChangeSeriesType( _
   ByVal sourceSeries As Series, _
   ByVal targetSeries As Series _
) 

Dim instance As SpreadChart
Dim sourceSeries As Series
Dim targetSeries As Series
 
instance.ChangeSeriesType(sourceSeries, targetSeries)

public void ChangeSeriesType( 
   Series sourceSeries,
   Series targetSeries
)

FpSpread1.Sheets[0].RowCount = 10;
FpSpread1.Sheets[0].ColumnCount = 10;
FpSpread1.Sheets[0].Cells[0, 1].Value = "c1";
FpSpread1.Sheets[0].Cells[0, 2].Value = "c2";
FpSpread1.Sheets[0].Cells[0, 3].Value = "c3";
FpSpread1.Sheets[0].Cells[1, 0].Value = "s1";
FpSpread1.Sheets[0].Cells[2, 0].Value = "s2";
FpSpread1.Sheets[0].Cells[3, 0].Value = "s3";
FpSpread1.Sheets[0].Cells[4, 0].Value = "s4";
FpSpread1.Sheets[0].Cells[5, 0].Value = "s5";
FpSpread1.Sheets[0].Cells[6, 0].Value = "s6";

FpSpread1.Sheets[0].Cells[1, 1].Value = 1;
FpSpread1.Sheets[0].Cells[2, 1].Value = 2;
FpSpread1.Sheets[0].Cells[3, 1].Value = 3;
FpSpread1.Sheets[0].Cells[4, 1].Value = 4;
FpSpread1.Sheets[0].Cells[5, 1].Value = 5;
FpSpread1.Sheets[0].Cells[6, 1].Value = 6;

FpSpread1.Sheets[0].Cells[1, 2].Value = 7;
FpSpread1.Sheets[0].Cells[2, 2].Value = 8;
FpSpread1.Sheets[0].Cells[3, 2].Value = 9;
FpSpread1.Sheets[0].Cells[4, 2].Value = 10;
FpSpread1.Sheets[0].Cells[5, 2].Value = 11;
FpSpread1.Sheets[0].Cells[6, 2].Value = 12;

FpSpread1.Sheets[0].Cells[1, 3].Value = 13;
FpSpread1.Sheets[0].Cells[2, 3].Value = 14;
FpSpread1.Sheets[0].Cells[3, 3].Value = 15;
FpSpread1.Sheets[0].Cells[4, 3].Value = 16;
FpSpread1.Sheets[0].Cells[5, 3].Value = 17;
FpSpread1.Sheets[0].Cells[6, 3].Value = 18;

FarPoint.Web.Spread.Model.CellRange range = new FarPoint.Web.Spread.Model.CellRange(1, 1, 1, 3);
FpSpread1.Sheets[0].AddChart(range, typeof(FarPoint.Web.Chart.BarSeries), 200, 200, 300, 0, FarPoint.Web.Chart.ChartViewType.View3D, false);
FarPoint.Web.Spread.Model.CellRange range1 = new FarPoint.Web.Spread.Model.CellRange(2, 1, 1, 3);
FpSpread1.Sheets[0].AddChart(range1, typeof(FarPoint.Web.Chart.LineSeries), 200, 200, 300, 200, FarPoint.Web.Chart.ChartViewType.View3D, false);

protected void Button1_Click(object sender, EventArgs e)
    {
FarPoint.Web.Spread.Chart.SpreadChart sourceChart = FpSpread1.Sheets[0].Charts[0];
FarPoint.Web.Chart.ChartModel targetModel = FpSpread1.Sheets[0].Charts[1].Model;
sourceChart.ChangeChartType(targetModel);
//uncomment this and comment the above to change the series type
//FarPoint.Web.Spread.Chart.SpreadChart sourceChart = FpSpread1.Sheets[0].Charts[0];
//FarPoint.Web.Chart.Series sourceSeries = FpSpread1.Sheets[0].Charts[0].Model.PlotAreas[0].Series[0];
//FarPoint.Web.Chart.Series targetSeries = FpSpread1.Sheets[0].Charts[1].Model.PlotAreas[0].Series[0];
//listBox1.Items.Add(sourceChart.CanChangeSeriesType(sourceSeries));
//sourceChart.ChangeSeriesType(sourceSeries, targetSeries);
    }

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
FpSpread1.Sheets(0).RowCount = 10
FpSpread1.Sheets(0).ColumnCount = 10
FpSpread1.Sheets(0).Cells(0, 1).Value = "c1"
FpSpread1.Sheets(0).Cells(0, 2).Value = "c2"
FpSpread1.Sheets(0).Cells(0, 3).Value = "c3"
FpSpread1.Sheets(0).Cells(1, 0).Value = "s1"
FpSpread1.Sheets(0).Cells(2, 0).Value = "s2"
FpSpread1.Sheets(0).Cells(3, 0).Value = "s3"
FpSpread1.Sheets(0).Cells(4, 0).Value = "s4"
FpSpread1.Sheets(0).Cells(5, 0).Value = "s5"
FpSpread1.Sheets(0).Cells(6, 0).Value = "s6"

FpSpread1.Sheets(0).Cells(1, 1).Value = 1
FpSpread1.Sheets(0).Cells(2, 1).Value = 2
FpSpread1.Sheets(0).Cells(3, 1).Value = 3
FpSpread1.Sheets(0).Cells(4, 1).Value = 4
FpSpread1.Sheets(0).Cells(5, 1).Value = 5
FpSpread1.Sheets(0).Cells(6, 1).Value = 6

FpSpread1.Sheets(0).Cells(1, 2).Value = 7
FpSpread1.Sheets(0).Cells(2, 2).Value = 8
FpSpread1.Sheets(0).Cells(3, 2).Value = 9
FpSpread1.Sheets(0).Cells(4, 2).Value = 10
FpSpread1.Sheets(0).Cells(5, 2).Value = 11
FpSpread1.Sheets(0).Cells(6, 2).Value = 12

FpSpread1.Sheets(0).Cells(1, 3).Value = 13
FpSpread1.Sheets(0).Cells(2, 3).Value = 14
FpSpread1.Sheets(0).Cells(3, 3).Value = 15
FpSpread1.Sheets(0).Cells(4, 3).Value = 16
FpSpread1.Sheets(0).Cells(5, 3).Value = 17
FpSpread1.Sheets(0).Cells(6, 3).Value = 18

Dim range As New FarPoint.Web.Spread.Model.CellRange(1, 1, 1, 3)
FpSpread1.Sheets(0).AddChart(range, GetType(FarPoint.Web.Chart.BarSeries), 200, 200, 300, 0, FarPoint.Web.Chart.ChartViewType.View3D, False)
Dim range1 As New FarPoint.Web.Spread.Model.CellRange(2, 1, 1, 3)
FpSpread1.Sheets(0).AddChart(range1, GetType(FarPoint.Web.Chart.LineSeries), 200, 200, 300, 200, FarPoint.Web.Chart.ChartViewType.View3D, False)
End Sub

Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
'Dim sourceChart As FarPoint.Web.Spread.Chart.SpreadChart
'sourceChart = FpSpread1.Sheets(0).Charts(0)
'Dim targetModel As FarPoint.Web.Chart.ChartModel
'targetModel = FpSpread1.Sheets(0).Charts(1).Model
'sourceChart.ChangeChartType(targetModel)
'uncomment this and comment the above to change the series type
Dim sourceChart As FarPoint.Web.Spread.Chart.SpreadChart
sourceChart = FpSpread1.Sheets(0).Charts(0)
Dim sourceSeries As FarPoint.Web.Chart.Series
Dim targetSeries As FarPoint.Web.Chart.Series
sourceSeries = FpSpread1.Sheets(0).Charts(0).Model.PlotAreas(0).Series(0)
targetSeries = FpSpread1.Sheets(0).Charts(1).Model.PlotAreas(0).Series(0)
ListBox1.Items.Add(sourceChart.CanChangeSeriesType(sourceSeries))
sourceChart.ChangeSeriesType(sourceSeries, targetSeries)
End Sub