To delete a chart sheet from a workbook, remove it from the workbook's ChartSheetCollection by using the ChartSheetCollection.Remove or ChartSheetCollection.RemoveAt method.
You can also move a chart back to the worksheet containing the source data by using the chart's ChartObject.MoveToWorksheet method.
// Create the first chart sheet.
// Create the second chart sheet.
// Remove the first chart sheet.