{...} Once an amendment has become law, portions of the original text may be deleted or new articles may be inserted among existing ones. The second, less common method, is for amendments to be appended to the end of the main text in the form of special articles of amendment, leaving the body of the original text intact. Although the wording of the original text is not altered, the doctrine of implied repeal applies. In other words, in the event of conflict, an article of amendment will usually take precedence over the provisions of the original text, or of an earlier amendment. Nonetheless, there may still be ambiguity as to whether an amendment is intended to supersede an existing article in the text or merely to supplement it. An article of amendment may, however, explicitly express itself as having the effect of repealing a specific existing article.
(See by way of example the 21st Amendment to the U.S. Constitution on the repeal of prohibition. Section 1 of the article repeals the 18th Amendment.)
The use of appended articles of amendment is most famous as a feature of the United States Constitution, but it is also the method of amendment in a number of other jurisdictions, such as Venezuela.
c/o Wikipedia:
http://en.wikipedia.org/wiki/Constitutional_amendment