Sub T1fr_Merge_3Col_Vert_en_1_sous_TST_BETTER2()

'From Forum, created by macropod Paul Edstein 2021-02-17
Application.ScreenUpdating = False
Dim Rng As range, r As Long, c As Long
With ActiveDocument.Tables(1)
  For c = .Columns.Count To 1 Step -1
    For r = .Rows.Count To 2 Step -1
      If c = .Columns.Count Then
        .Columns.Add
      Else
        .Columns.Add .Columns(c + 1)
      End If
      .AutoFitBehavior wdAutoFitWindow
      Set Rng = .cell(r, c).range
      Rng.End = Rng.End - 1
      .cell(1, c + 1).range.FormattedText = Rng.FormattedText
    Next
  Next
  For r = .Rows.Count To 2 Step -1
    .Rows(r).Delete
  Next
End With
Application.ScreenUpdating = True

End Sub