(a) To the extent not prohibited by the Constitution of the United States or of this State, the charter of each religious corporation subject to this part and incorporated before June 1, 1957, is deemed to be amended to conform to the constitution of the United Presbyterian Church in the United States of America and its successors, as from time to time in effect.

(b) The charter of a religious corporation subject to this part may not be amended in any way that conflicts with the constitution of the United Presbyterian Church in the United States of America and its successors, as from time to time in effect.