The 21st amendment (which I find hilarious considering the subject matter and the age people are allowed to drink legally in the US) has the unique situation of being the only amendment to full out repeal another.
The eighteenth article of amendment to the Constitution of the United States is hereby repealed.
The transportation or importation into any State, Territory, or Possession of the United States for delivery or use therein of intoxicating liquors, in violation of the laws thereof, is hereby prohibited.
This article shall be inoperative unless it shall have been ratified as an amendment to the Constitution by conventions in the several States, as provided in the Constitution, within seven years from the date of the submission hereof to the States by the Congress
The 21st amendment was ratified in December of 1933, having been passed by congress in February of that year. So it came in well under the ratification deadline. Its sole purpose really is to repeal the 18th amendment.
Section one is self explanatory, as that is where they tell you that the 18th amendment, prohibiting alcohol, was repealed. Section two continues to hold up state rights in this manner, explaining that even if its now legal in the US to transport alcohol,if a State still prohibits it then its still illegal within that state’s borders. This is how you get some states where you can purchase your alcohol at your gas station, while other states you have to purchase it at specially licensed stores and distributers.
Section three basically allows for this law to become active at a certian time after the ratification, and also gives it a limit on how long it could take. Thus we don’t have to wait 100 years like we did on the 27th amendment (which we will of course get to).
So this amendment not only doesn’t actually edit the constitution, it actually only serves to repeal an earlier amendment. It was the first (and only to my knowledge) amendment to do so.