The lower house of parliament gave initial approval to President Vladimir Putin’s plan to make major changes to the constitution, widely seen as an effort by the Russian leader to extend his 20-year rule. Legislators in the State Duma rose for a standing ovation after voting 432-0 for the proposal, which Putin unveiled in a surprise announcement last week. Discussions on possible amendments are set for next week, with a vote on those scheduled on Feb. 11. The plan will go to a national vote in April and is virtually certain to pass. The amendments, the most dramatic since the constitution was adopted in 1993, would reduce the power of the presidency, giving somewhat more authority to the parliament and strengthening the State Council, now a largely ceremonial body. The overhaul could create options for Putin to retain control after his current term — his last under constitutional limits — ends in 2024.