Mignon Clyburn, a Democrat who has served for eight years as one of five commissioners of the Federal Communications Commission, said she will resign from the regulatory body before its next open meeting in May.

She made the announcement during an FCC meeting today. “I’ve done all I know to do. And it’s time for me to serve in another way,” she said, according to multiple press accounts of the meeting.

Clyburn’s departure leaves an empty seat on the commission, which is in the midst of several high-profile rule and transaction reviews. The commissioners are all appointed by the president. President Donald Trump has made eliminating regulation a key priority of his administration and Chairman Ajit Pai, who was appointed by President Barack Obama, has acted quickly to strip away decades of rules. In some cases, such as the FCC’s review of Sinclair Broadcasting Group’s pending acquisition of Tribune Media, Democratic members of Congress have raised alarms by the speed and intensity of the de-regulatory shift.

Clyburn, a Barack Obama appointee who briefly served as Chairman of the FCC in 2016, marking the first time a woman has held that post, has been a fiery critic of the Republican-led effort to roll back net neutrality rules. She had led the effort to pass the rules in 2015, a move that backers, including then-Chairman Tom Wheeler, felt would prevent the concept of internet “fast lanes” and a commercialized system of access based on pay tiers and corporate favoritism. Pai, who voted against the plan in 2015, said in steering the rollback that it was an effort to offer “freedom” to businesses providing internet and broadband service. Pai and others said the rules were stifling innovation and investment. Clyburn issued a statement after the February net neutrality vote calling it “another anti-consumer notch in this FCC’s belt.”

In a statement, Pai congratulated Clyburn on her “distinguished tenure” at the FCC. “I have enjoyed working with her and, even when we have not seen eye-to-eye on policy, I have always held her candor and thoughtfulness in the highest regard,” Pai said. “She’s been a wonderful colleague and friend. I wish her nothing but the best and sincerely thank her for her service.”

This tweet has been pinned at the top of Clyburn’s official handle since February: