An official change to the Constitution is called an amendment. Out of the 5,000 amendments that have been introduced by Congress, only 27 have been ratified, or accepted.
Article V of the Constitution establishes a process for amending the Constitution in a two-step process: proposal of an amendment and ratification. An amendment must be passed by a two-thirds vote in both the House of Representatives as well as the Senate. Some of the most significant amendments include the 19th, which gave women the right to vote, the 13th, which abolished slavery and the 14th, which gave citizenship to former slaves.