- In 1781 the State of Massachusetts Bay became the Commonwealth of Massachusetts.
- In 2020 the State of Rhode Island and Providence Plantations became the State of Rhode Island (when most people who didn't live there had long been unaware that the abbreviated name was not the full official name).
Both of these changes were accomplished by a referendum to alter the constitution of the state.
Are there other instances?
(I knew of the old name of Rhode Island from having read (1) the Declaration of Independence, promulgated in 1776, (2) the Articles of Confederation, proposed by Congress in 1777 and ratified and effective in 1781, (3) the Definitive Treaty of Peace that ended the war of American independence, signed in 1783 and ratified and effective in 1784, and (4) the Constitution of the United States, proposed by Convention in 1787 and ratified and effective in 1788. But in 2000 when I visited Rhode Island, I didn't know whether that old name was still official until I saw, posted in an elevator, one of those certificates that the elevator had been found in compliance with regulations. The old name was esoteric except in Rhode Island.)