Why does Recep-Tayyip Erdogan decide to change the constitution?

It was a triumphant moment for Turkey’ s most powerful politician in a generation—Recep-Tayyip Erdogan sworn in as the country’ s first elected president, a previously ceremonial post.He’ s vowed to change the constitution to increase his power, but that is to come.Today the focus was on his oath of office.He swore allegiance to Turkey’ s sovereignty and its founding principle of secularism.But that, say his critics, is what he no longer upholds.