Write to XLS file without using Office client application ?

https://support.microsoft.com/en-us/kb/257757 said "Microsoft strongly recommends a number of alternatives that do not require Office to be installed server-side, and that can perform most common tasks more efficiently and more quickly than Automation.
Most server-side Automation tasks involve document creation or editing. Office 2007 supports new Open XML file formats that let developers create, edit, read, and transform file content on the server side. These file formats use the System.IO.Package.IO namespace in the Microsoft .NET 3.x Framework to edit Office files without using the Office client applications themselves. This is the recommended and supported method for handling changes to Office files from a service."

Currently, I have a program that uses an existing XLS that already format the column headers with colors and has formulas for some cells, runs a Macro in an XLS file that queries a TXT file, creates a Pivot table, and save the XLS sheet to a different XLS file.
Below is an example of the XLS column header. There are formulas behind the $0 (for ex: =SUMIF(B6:B31378,"=Open",K6:K31378)

The codes for the Macro is the below.
How can I do this without using Office client application ?
Thank you.

Sub myMacro(Var1, Var2)
    With ActiveSheet.QueryTables.Add(Connection:= _"TEXT;" & Var1, Destination:=Range("A6"))
        .Name = "oc_1"
        .FieldNames = True
        .RowNumbers = False
        .FillAdjacentFormulas = False
        .PreserveFormatting = True
        .RefreshOnFileOpen = False
        .RefreshStyle = xlInsertDeleteCells
        .SavePassword = False
        .SaveData = True
        .AdjustColumnWidth = True
        .RefreshPeriod = 0
        .TextFilePromptOnRefresh = False
        .TextFilePlatform = 437
        .TextFileStartRow = 1
        .TextFileParseType = xlDelimited
        .TextFileTextQualifier = xlTextQualifierDoubleQuote
        .TextFileConsecutiveDelimiter = False
        .TextFileTabDelimiter = False
        .TextFileSemicolonDelimiter = False
        .TextFileCommaDelimiter = False
        .TextFileSpaceDelimiter = False
        .TextFileOtherDelimiter = "|"
        .TextFileColumnDataTypes = Array(1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, _
        1, 1, 1, 1)
        .TextFileTrailingMinusNumbers = True
        .Refresh BackgroundQuery:=False
    End With
    Rows("6:6").Select
    Range(Selection, Selection.End(xlDown)).Select
    ActiveWorkbook.PivotCaches.Add(SourceType:=xlDatabase, SourceData:= _"OC_Report!R5C1:R25000C23").CreatePivotTable TableDestination:="", _
        TableName:="PivotTable1", DefaultVersion:=xlPivotTableVersion10
    ActiveSheet.PivotTableWizard TableDestination:=ActiveSheet.Cells(3, 1)
    ActiveSheet.Cells(3, 1).Select
    ActiveSheet.PivotTables("PivotTable1").RowGrand = False
    ActiveSheet.PivotTables("PivotTable1").AddFields RowFields:=Array("Firm", _"open/" & Chr(10) & "closed")
    ActiveSheet.PivotTables("PivotTable1").PivotFields("open/" & Chr(10) & "closed").Orientation _
        = xlDataField
        Worksheets("OC_Report").Activate
        ActiveSheet.Range("A6").Select

    Worksheets("Sheet1").Activate
    Sheets("Sheet1").Select
    Sheets("Sheet1").Name = "OCF"

    Worksheets("OC_Report").Activate
    ActiveSheet.Range("A6").Select

    Dim active As Workbook
    Set active = Application.ThisWorkbook

    Dim wb As Workbook
    Set wb = Workbooks.Add

    active.Activate
        Sheets("OC_Report").Select
        Sheets("OC_Report").Copy Before:=Workbooks(wb.Name).Sheets(1)
    active.Activate
        Sheets("OCF").Select
        Sheets("OCF").Copy After:=Workbooks(wb.Name).Sheets(1)
    active.Activate
        Sheets("MyTab2").Select
        Sheets("MyTab2").Copy After:=Workbooks(wb.Name).Sheets(1)

    wb.Sheets("Sheet1").Delete

    ActiveWorkbook.SaveAs Filename:= _
        Var2, FileFormat:=xlNormal, _
        Password:="", WriteResPassword:="", ReadOnlyRecommended:=False, _
        CreateBackup:=False
End Sub