
Extract the answer to the question from the following context.
Question: What needed to be changed in order for the name to be legal?
Context: On December 25, 1991, following the collapse of the Soviet Union, the republic was renamed the Russian Federation, which it remains to this day. This name and "Russia" were specified as the official state names in the April 21, 1992 amendment to the existing constitution and were retained as such in the 1993 Constitution of Russia.

amendment to the existing constitution
