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].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.Win.Spread.Model.CellRange range = new FarPoint.Win.Spread.Model.CellRange(1, 1, 1, 3);
fpSpread1.Sheets[0].AddChart(range, typeof(FarPoint.Win.Chart.BarSeries), 200, 200, 300, 0, FarPoint.Win.Chart.ChartViewType.View3D, false);
FarPoint.Win.Spread.Model.CellRange range1 = new FarPoint.Win.Spread.Model.CellRange(2, 1, 1, 3);
fpSpread1.Sheets[0].AddChart(range1, typeof(FarPoint.Win.Chart.LineSeries), 200, 200, 300, 200, FarPoint.Win.Chart.ChartViewType.View3D, false);

private void button1_Click(object sender, EventArgs e)
{            
FarPoint.Win.Spread.Chart.SpreadChart sourceChart = fpSpread1.Sheets[0].Charts[0];
FarPoint.Win.Chart.ChartModel targetModel = fpSpread1.Sheets[0].Charts[1].Model;
sourceChart.ChangeChartType(targetModel);
//uncomment this and comment the above to change the series type
//FarPoint.Win.Spread.Chart.SpreadChart sourceChart = fpSpread1.Sheets[0].Charts[0];
//FarPoint.Win.Chart.Series sourceSeries = fpSpread1.Sheets[0].Charts[0].Model.PlotAreas[0].Series[0];
//FarPoint.Win.Chart.Series targetSeries = fpSpread1.Sheets[0].Charts[1].Model.PlotAreas[0].Series[0];
//listBox1.Items.Add(sourceChart.CanChangeSeriesType(sourceSeries));
//sourceChart.ChangeSeriesType(sourceSeries, targetSeries);
}

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

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim sourceChart As FarPoint.Win.Spread.Chart.SpreadChart
sourceChart = FpSpread1.Sheets(0).Charts(0)
Dim targetModel As FarPoint.Win.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.Win.Spread.Chart.SpreadChart
'sourceChart = FpSpread1.Sheets(0).Charts(0)
'Dim sourceSeries As FarPoint.Win.Chart.Series
'Dim targetSeries As FarPoint.Win.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