=IF(ISNUMBER(FILTER(A2:D19,A2:A19="Fritz")),IFS(FILTER(A2:D19,A2:A19="Fritz")>5000,"Above Target",FILTER(A2:D19,A2:A19="Fritz")>3000,"On Target",FILTER(A2:D19,A2:A19="Fritz")<2500,"Below Target"),FILTER(A2:D19,A2:A19="Fritz"))

//Create a new workbook
var workbook = new GrapeCity.Documents.Excel.Workbook();          
​
//Load sample data from excel file
workbook.Open("SampleData.xlsx");
​
//Enable dynamic array formula
workbook.AllowDynamicArray = true;

//Fetch worksheet
var worksheet = workbook.Worksheets[0];
​
//Fetch the original formula which needs to be parsed.
var originalFormula = worksheet.Range["H3"].Formula.Substring(1);

//Method to parse a formula and print the syntax tree
public static void ParseAndPrint(IWorksheet worksheet, string formula)
{
  // Get syntax tree
  var syntaxTree = FormulaSyntaxTree.Parse(formula);
​
  // Flatten nodes
  var displayItems = new List<(string TypeName, int IndentLevel, string Content)>();
​
  void flatten(SyntaxNode node, int level)
  {
    displayItems.Add((node.GetType().Name, level, node.ToString()));
    foreach (var child in node.Children)
    {
        flatten(child, level + 1);
    }
  }
​
  flatten(syntaxTree.Root, 0);
​
  // Output          
  worksheet.ShowRowOutline = false;
  worksheet.OutlineColumn.ColumnIndex = 1;
​
  // Header
  worksheet.Range["A1"].Value = "Formula";
  worksheet.Range["A3"].Value = "Syntax node";
  worksheet.Range["B3"].Value = "Part";
​
  // Values
  worksheet.Range["B1"].Value = "'=" + formula;
  for (var i = 0; i < displayItems.Count; i++)
  {
    var item = displayItems[i];
    var text = "'" + item.TypeName;
​
    worksheet.Range[i + 4, 0].Value = text;
    worksheet.Range[i + 4, 0].IndentLevel = item.IndentLevel;
    worksheet.Range[i + 4, 1].Value = "'" + item.Content;
  }
​
  //Apply styling
  worksheet.Range["A1:B3"].Interior.Color = System.Drawing.Color.FromArgb(68, 114, 196);
  worksheet.Range["A1:B3"].Font.Color = System.Drawing.Color.White;
  worksheet.Range["A1:B3"].Borders.Color = System.Drawing.Color.FromArgb(91, 155, 213);
  worksheet.Range["A1:B3"].Borders.LineStyle = BorderLineStyle.Thin;
  worksheet.Range["A1,A3,B3"].Font.Size = 14;
  worksheet.Range["A1,A3,B3"].Font.Bold = true;
  worksheet.Range["A:C"].EntireColumn.AutoFit();          
}

//Method to parse and modify the formula
public static void ModifyFormula(IWorksheet worksheet, string originalFormula)
{
  //Apply UNIQUE formula to get unique sales representatives list
  worksheet.Range["F1"].Value = "Unique Rep";
  worksheet.Range["F2"].Formula = "=UNIQUE(A2:A19)";
  var uniqueRep = worksheet.Range["F2#"];
  // Apply Styling
  worksheet.Range["F:F"].EntireColumn.AutoFit();
  worksheet.Range["F1"].Interior.Color = System.Drawing.Color.FromArgb(68, 114, 196);
  worksheet.Range["F1"].Font.Color = System.Drawing.Color.White;
  worksheet.Range["F2#"].Borders.Color = System.Drawing.Color.FromArgb(91, 155, 213);
  worksheet.Range["F2#"].Borders.LineStyle = BorderLineStyle.Thin;
​
  //Get syntax tree
  var syntaxTree = FormulaSyntaxTree.Parse(originalFormula);
​
  //Find
  var findText = new TextNode("Fritz");
​
  //Replacement
  var replaceText = new TextNode("");
​
  //Loop through names list to modify the formula for each sales representative
  for (int r = 0, resultRow = 3; r < uniqueRep.Cells.Count; r++, resultRow = resultRow + 4)
  {
      //Get name to be replaced in the formula
      var cval = uniqueRep.Cells[r].Value.ToString();
​
      if (findText.Value != cval)
      {
        //Assign name to be replaced to Replace TextNode
        replaceText.Value = cval;
​
        //Invoke the recursive method to perform find and replace operation
        replaceNode(syntaxTree.Root, findText, replaceText);
​
        //Assign the modified formula to a cell in the worksheet
        var resultRange = "H" + resultRow.ToString();
        worksheet.Range[resultRange].Formula = "=" + syntaxTree.ToString();
        worksheet.Range[resultRange + "#"].Borders.Color = System.Drawing.Color.FromArgb(91, 155, 213);
        worksheet.Range[resultRange + "#"].Borders.LineStyle = BorderLineStyle.Thin;
​
        //Update the value of Find node to perform find and replace operation for next sales representative name
        findText = replaceText;
      }
  }
​
  //Find and replace
  void replaceNode(SyntaxNode lookIn, SyntaxNode find, SyntaxNode replacement)
  {
      var children = lookIn.Children;
​
      for (var i = 0; i < children.Count; i++)
      {
        var child = children[i];
        if (child.Equals(find))
        {
            children[i] = replacement;
        }
        else
        {
            replaceNode(child, find, replacement);
        }
      }
  }
}

=IF(ISNUMBER(FILTER(A2:D19,A2:A19="Xi")),IFS(FILTER(A2:D19,A2:A19="Xi")>5000,"Above Target",FILTER(A2:D19,A2:A19="Xi")>3000,"On Target",FILTER(A2:D19,A2:A19="Xi")<2500,"Below Target"),FILTER(A2:D19,A2:A19="Xi"))

//Save modified Excel file
workbook.Save("ModifiedFormula.xlsx", SaveFileFormat.Xlsx);