[Dirk Diggler]

Пардон, сам разобрался. Конечный вариант(разъединяет текущую ячейку вниз)

Код:

Sub UNM()
Dim iROW As Integer, iColumn As Integer, sTMP As String, i As Integer, s As Range
    Application.ScreenUpdating = False
    Set s = ActiveCell
          If ActiveWorkbook.ActiveSheet.Cells(s.Row + iROW, s.Column).MergeCells Then
                i = ActiveWorkbook.ActiveSheet.Cells(s.Row + iROW, s.Column).MergeArea.Count - 1
                ActiveWorkbook.ActiveSheet.Cells(s.Row + iROW, s.Column).MergeArea.UnMerge
          End If
    s.Select
    ActiveCell.Offset(1, 0).Select
    Do While IsEmpty(ActiveCell) And i > 0
      i = i - 1
      ActiveCell.Value = s.Value
      ActiveCell.Offset(1, 0).Select
    Loop
End Sub