Private Sub Document_ContentControlOnExit(ByVal ContentControl As ContentControl, Cancel As Boolean)
Dim i As Long, j As String, Rng As Range
With ContentControl
  If .Type <> wdContentControlDate Then Exit Sub
  If .Title = "MyDate" Then
    If .ShowingPlaceholderText Then Exit Sub
    .Type = wdContentControlRichText
    Set Rng = .Range
    For i = 0 To UBound(Split(.Range.Text, " "))
      j = Split(.Range.Text, " ")(i)
      If IsNumeric(j) Then
        With Rng
          .Start = .Start + InStr(ContentControl.Range.Text, j) + Len(j) - 1
          .End = .Start
          .InsertAfter Ordinal(Val(j))
          .Font.Superscript = True
        End With
        .Type = wdContentControlDate
        Exit For
      End If
    Next
  End If
End With
End Sub
 
Function Ordinal(Val As Integer) As String
Dim strOrd As String
If (Val Mod 100) < 11 Or (Val Mod 100) > 13 Then strOrd = Choose(Val Mod 10, "st", "nd", "rd") & ""
Ordinal = IIf(strOrd = "", "th", strOrd)
End Function