Rep. Stephen F. Lynch (Mass.) walks with House Minority Leader Nancy Pelosi (Calif.) as they leave a closed-door meeting at the Capitol Visitor Center Auditorium last week to nominate a speaker and choose other members of the Democratic leadership team. (Sarah L. Voisin/The Washington Post)

Democratic Rep. Stephen F. Lynch, who had opposed Rep. Nancy Pelosi’s bid for House speaker, reversed course and announced on Friday that he will support her candidacy.

It was the latest boost to Pelosi’s bid to regain the speaker’s gavel after eight years in the minority and the latest blow to the small band of Democrats who are threatening to withhold their votes to force a shake-up in the party’s top ranks.

Lynch (Mass.) had signed a letter last month calling for “new leadership” at the top of the party, joining 15 colleagues. But on Friday he said Pelosi (D-Calif.) had his “full support” following “several days of productive conversations and growing clarity on the future direction and priorities of the Democratic House.”

Lynch’s reversal puts Pelosi closer to securing the votes she needs to win in a scheduled Jan. 3 election, though she still remains several votes short.

A Washington Post tally counts 22 Democrats who are now openly opposed to her, with another 18 dodging questions about their positions. She can afford to lose up to 17 Democratic votes if all members vote for an individual.

But Pelosi has doggedly worked to win over her critics. Last month, Pelosi secured the support of Rep. Marcia L. Fudge (D-Ohio), who was considering a run against her, and of Rep. Brian Higgins (D-N.Y.), who signed the letter with Lynch.

One incoming freshman, Rep.-elect Haley Stevens (D-Mich.), also said this week she planned to vote for Pelosi next month after saying she wanted new leadership during her campaign and voting against Pelosi last month in a party nominating vote.

“I was clear going into that vote with her and the rest of the leadership about where I would be,” she told the Oakland Press, a local paper in Michigan. “I was also clear with her that I wouldn’t be voting against her on the House floor in January.”

A larger group of Democrats are now negotiating with the 78-year-old Pelosi — who has been the top House Democrat for nearly 16 years — in hopes of getting younger members a greater role in the party leadership. One of them, Rep. Ed Perlmutter (D-Colo.), said last week that he is seeking to secure “some kind of transition” in an interview.

One point of negotiation could surround implementing term limits on Democratic committee chairmen for the first time. While Republicans limit their committee chairs to three terms, Democrats have adhered to a seniority-based system, and many minority lawmakers credit that with allowing them to rise up the ranks.

But it has also led to frustrations among younger members who are faced with spending decades before they reach the upper echelons of legislative influence.

Pelosi, who has previously considered and rejected moving away from the seniority system, said Thursday that she was “sympathetic” to younger members’ concerns but declined to endorse it outright.

“I say that’s a debate for the caucus to have, and we will have that,” she said.

Meanwhile, other members are more interested in advancing their personal priorities than turnover in the leadership ranks. Lynch, in a statement, said he was assured that “average working families” would be foremost in the new Congress.

“In the recent past, working-class Democrats have felt that they were taken for granted in our party and candidate Donald Trump exploited that perception,” he said. “My goal was to get some reassurances that we are going to adopt an agenda that will include a real focus on issues that will make life better for the every working family,” he said, citing such issues pension reform, infrastructure, roads and bridges and college affordability.

Lynch, a member of the House Oversight and Government Reform committee, said he had also won commitments from Pelosi to support that panel’s work investigating the Trump administration and “will be encouraged to follow the facts wherever they may lead.”