Sub Demo()
Application.ScreenUpdating = False
Dim Rng As Range
With ActiveDocument.Range
  With .Find
    .ClearFormatting
    .Replacement.ClearFormatting
    .Text = "([0-9])[Xx]"
    .Replacement.Text = ""
    .Forward = True
    .Wrap = wdFindStop
    .Format = False
    .MatchWildcards = True
    .Execute
  End With
  Do While .Find.Found
    Set Rng = .Duplicate
    .Duplicate.Characters.Last = "x"
    With Rng
      .Start = .Duplicate.End + 1
      Do
        If Not .Characters.Last Like "[/" & vbCr & "]" Then
          .End = .End + 1
        Else
          Exit Do
        End If
      Loop
      If InStr(1, .Text, "x", vbTextCompare) > 0 Then .Text = Replace(.Text, "x", ".", 1, , vbTextCompare)
    End With
    .Start = Rng.End
    .Find.Execute
  Loop
End With
Application.ScreenUpdating = True
End Sub