Helaine Olen writes in Slate:
Within a day of the election, House Speaker Paul Ryan, who champions a plan to turn Medicare into a voucher system, was talking reform. Price supports this plan. Mick Mulvaney, Trump’s selection to head up the Office of Management and Budget, is as unhappy with Medicare as he is with Social Security. Trump’s said nothing to date, but just days after the election, his transition website proclaimed he would “modernize Medicare.” Voucherizing Medicare definitely qualifies as a serious cut. Seniors would receive a set amount to apply toward the purchase of approved insurance plans. If they pick an option that costs more than their stipend, they pay the excess cost.
In 2013, the Congressional Budget Office estimated that the latest version of Ryan’s premium-support idea would generate savings for both the government and Medicare beneficiaries without reducing benefit levels. So no, it doesn’t “definitely” qualify as a cut in benefits, serious or otherwise.