In a nationally televised speech early in the morning of December 25, 1991, Gorbachev resigned as president of the USSR – or, as he put it, "I hereby discontinue my activities at the post of President of the Union of Soviet Socialist Republics." He declared the office extinct, and all of its powers (such as control of the nuclear arsenal) were ceded to Yeltsin. A week earlier, Gorbachev had met with Yeltsin and accepted the fait accompli of the Soviet Union's dissolution. On the same day, the Supreme Soviet of the Russian SFSR adopted a statute to change Russia's legal name from "Russian Soviet Federative Socialist Republic" to "Russian Federation," showing that it was now a sovereign state.
How did Gorbachev declare his resignation?
resigned as president of the USSR – or, as he put it, "I hereby discontinue my activities at the post of President of the Union of Soviet Socialist Republics