You could, of course, use something like:
Code:
Private Sub Document_ContentControlOnExit(ByVal CCtrl As ContentControl, Cancel As Boolean)
With CCtrl
If .Title = "Dropdown1" Then
If .Range.Text = "Date" Then
.Type = wdContentControlDate
.Range.Text = ""
.Range.Select
ElseIf .Range.Text = .PlaceholderText Then
.Type = wdContentControlDropdownList
.Range.Select
End If
End If
End With
End Sub
and have 'Date' as one of the dropdown choices.