Ontological change of clerical orders?

[Gregory]

I have been told that only the subdeacon and up have an ontological change but this does not seem correct to me. Perhaps in this case ontological has a different meaning.

Is it not true that a king, who having attained the relational accident of king, have undergone some sort of ontological change?

Also I think here St. Thomas proves that the minor orders undergo an ontological change.

ST III, Q35, A2

Article 2. Whether in the sacrament of Order a character is imprinted in connection with all the Orders?

I answer that, There have been three opinions on this point. For some have said that a character is imprinted only in the Order of priesthood; but this is not true, since none but a deacon can exercise the act of the diaconate, and so it is clear that in the dispensation of the sacraments, he has a spiritual power which others have not. For this reason others have said that a character is impressed in the sacred, but not in the minor*, Orders. But this again comes to nothing, since each Order sets a man above the people in some degree of authority directed to the dispensation of the sacraments. Wherefore since a character is a sign whereby one thing is distinguished from another, it follows that a character is imprinted in each Order. And this is confirmed by the fact that they remain for ever and are never repeated. This is the third and more common opinion.