Changing the structure of a csv file

This does all the formatting in memory so it should be pretty fast.

Option Explicit

Sub CSVconverter()
Dim wbCSV As Workbook, MyArr As Variant, NewArr As Variant
Dim LR As Long, NR As Long, i As Long, j As Long

    With Application.FileDialog(msoFileDialogFilePicker)
        .Filters.Clear
        .AllowMultiSelect = False
        .Filters.Add "CSV Files", "*.csv", 1  'default
        .ButtonName = "SELECT"
        .Title = "Select CSV file"
        .Show
        If .SelectedItems.Count > 0 Then
            Set wbCSV = Workbooks.Open(.SelectedItems(1))
        Else
            Exit Sub
        End If
    End With

    LR = Range("A" & Rows.Count).End(xlUp).Row
    MyArr = Range("A1:N" & LR).Value
    ReDim NewArr((WorksheetFunction.Count(Range("A1:N" & LR)) + 1000), 2)
    NewArr(0, 1) = "Date": NewArr(0, 2) = "Value"
    NR = 1

    For i = 2 To UBound(MyArr, 1)
        For j = 3 To 14
            If IsDate(MyArr(1, j) & " " & MyArr(i, 2) & ", " & MyArr(i, 1)) Then
                NewArr(NR, 1) = Format(DateValue(MyArr(1, j) & " " & MyArr(i, 2) & ", " & MyArr(i, 1)), "MM/DD/YYYY")
                NewArr(NR, 2) = MyArr(i, j)
                NR = NR + 1
            End If
        Next j
    Next i

    Sheets.Add
    Range("A1:C" & UBound(NewArr)).Value = NewArr
    Range("A:A").Delete xlShiftToLeft
    Range("A:B").Sort Range("A2"), xlAscending, Header:=xlYes
    ActiveSheet.Move
    Application.DisplayAlerts = False
    ActiveWorkbook.SaveAs Filename:=Replace(wbCSV.FullName, ".csv", "-NEW.csv"), FileFormat:=xlCSV, CreateBackup:=False
    ActiveWorkbook.Close False
    wbCSV.Close False
    
End Sub