XIII. Amendment of the Constitution
(1) An amendment of the Constitution can be carried out on the initiative: (a) of the President of the Republic, (b) of the Government or (c) of one quarter of the statutory number of deputies.
(2) The motion made by the President of the Republic can be voted upon only in its entirety and without amendments or with amendments to which the Government, on behalf of the President of the Republic, agrees.
(3) A law amending the Constitution on the initiative of the President of the Republic requires concurrent decisions of the Seym and Senate passed by an ordinary majority vote; if on the initiative of the Government or the Seym — concurrent decisions passed by a majority of the statutory number of deputies and senators.
(4) The President of the Republic may within thirty days after having received the project of a law amending the Constitution refer it back to the Seym with the demand that it be reconsidered, which can take place not earlier than during the subsequent term.
(5) If the Legislative Chambers again pass the project without amendments, the President of the Republic shall after having confirmed the law with his signature promulgate it unless he dissolves the Seym and Senate.