Northern Ireland Secretary Karen Bradley said she’s open-minded about the two customs options being shuffled by the U.K. government, suggesting she could perhaps withdraw support for Prime Minister Theresa May’s preferred plan.

May’s inner Brexit Cabinet split 6-5 two weeks ago on the two options for Britain’s future trading relationship with the European Union, with May in the minority, alongside Bradley. But appearing before the House of Commons European Scrutiny Committee on Wednesday, Bradley signaled she’s open to changing her mind.

“Both could possibly work, but there are concerns,” Bradley told lawmakers. “I have an open mind and I really want to drill down on what is proposed and what options are available to see whether it is possible to make either option work.”

At stake is the nature of Britain’s trading relationship with the EU after Brexit, and what barriers are put in place for exporters and importers. While the EU has dismissed both options as unworkable, it’s begun to engage, at least, on May’s preferred so-called customs partnership plan. If Bradley switched sides, it could be the final nail in the coffin for the premier’s chosen solution.

That option would see Britain levying tariffs at EU rates, providing refunds for goods destined to British markets if U.K. tariffs are lower. The plan preferred by the pro-Brexit camp, called “maximum facilitation,” would use trusted trader programs and technology to regulate the border.

The premier has tasked Bradley and Business Secretary Greg Clark to work to improve the max fac plan in conjunction with Brexit Secretary David Davis, the only minister of the three to support it. Environment Secretary Michael Gove and Trade Secretary Liam Fox are focusing on the partnership plan with May’s de facto deputy, Cabinet Office Minister David Lidington, himself the only supporter of the option of the three.

Bradley said that the advantage of the partnership plan would be not changing the way the common external tariff on goods is collected, enabling easier cross-border trade between Ireland and Norther Ireland. The benefits of maximum facilitation are that it allows Britain to pursue an independent trade policy, she said. Ultimately, whatever solution is chosen needs to ensure no hard border in Ireland or the Irish Sea and as frictionless trade as possible, she said.

Bradley stuck to the line that both could work, declining to say which she thought would be ultimately chosen. “I’m not here as a person, I’m here as a secretary of state,” she said at the end of the hearing when asked for her personal views.