Hello wmr,
This version of the macro should be easier to understand and modify. It will add the Duplicates Conditional Formatting to column D, F, H, and J starting with row 2 down to the last row in column "A".
Sub AddCondFormat()
Dim i As Long
Dim LastRow As Long
Dim Rng As Range
Dim Wks As Worksheet
Set Wks = Worksheets("Duplicate Names")
Set Rng = Range("D2, F2, H2, J2, L2")
LastRow = Wks.Cells(Rows.Count, "A").End(xlUp).Row
If LastRow < Rng.Row Then Exit Sub
For i = 0 To LastRow - Rng.Row
For Each Cell In Rng.Offset(i, 0)
With Cell
.FormatConditions.Delete
With .FormatConditions
.Add xlUniqueValues
.Item(1).ModifyAppliesToRange Rng.Offset(i, 0)
.Item(1).DupeUnique = xlDuplicate
.Item(1).Font.Color = -16383844
.Item(1).Font.TintAndShade = 0
.Item(1).Interior.PatternColorIndex = xlAutomatic
.Item(1).Interior.Color = 13551615
.Item(1).Interior.TintAndShade = 0
.Item(1).StopIfTrue = False
End With
End With
Next Cell
Next i
End Sub