National Taxpayer Advocate Nina Olson will retire at the end of July after 18 years as its chief and said last week that she is forming a nonprofit outside of the government to continue to champion taxpayers’ rights.

Olson spoke candidly June 21 in a tax forum hosted by New York University School of Professional Studies. Olson said she sometimes experienced tensions with IRS leadership in her role as head of the Taxpayer Advocate Service, an independent office that exists to identify systemic problems within the IRS and propose administrative or legislative changes to mitigate those problems and improve the taxpayers’ experience.

Last summer, according to Bloomberg BNA, Olson said she expressed concerns publicly with the IRS’s implementation of the 2017 tax law’s repatriation tax, a one-time levy on accumulated offshore earnings. She was told by IRS leadership that she was “not a team player.”

“My role is not to be a shill for the IRS,” Olson told the audience.

The new nonprofit organization Olson is forming is called the Center for Taxpayer Rights. One of the first issues the nonprofit tackles may be a provision in the 2017 tax law that requires taxpayers to provide a Social Security number to claim the full child tax credit. Olson said some religious groups, such as the Amish, do not obtain Social Security numbers because it’s against their religious beliefs to participate in social welfare programs.