Sub test()
    Dim rng As Range, r As Range, x, i As Long
    On Error Resume Next
    Set rng = Cells.SpecialCells(2)
    On Error GoTo 0
    If rng Is Nothing Then Exit Sub
    With CreateObject("vbscript.regexp")
        .IgnoreCase = True
        .Pattern = "(.*)(x)(.*)(\2)(.*)"
        For Each r In rng
            x = Split(LCase$(r.Value), "/")
            For i = 0 To UBound(x)
                Do While  .test(x(i))
                    x(i) = .Replace(x(i), "$1x$3.$5")
                Loop
            Next
            r.Value = Join$(x, "/")
        Next
    End With
    Set rng = Nothing
End Sub