(CNN) House Speaker Nancy Pelosi said Thursday that the process of improving the Affordable Care Act "may lead to 'Medicare for All,' " suggesting that she could prove amenable to the health care proposal that has become a rallying cry for many progressives.

The comments highlighted the speaker's shifting tone in addressing the relationship between the two plans supported by Democrats.

Pelosi told Bloomberg last month that she was "not a big fan of Medicare for All," citing "its complications" and instead plugged the Affordable Care Act -- spearheaded by President Barack Obama, and crafted with Pelosi's own input during her previous tenure as speaker -- as "the path to health care for all Americans."

Any improvements to the Affordable Care Act are unlikely unless Democrats win full control of Congress, however.

When asked during a CNN town hall Thursday evening about her views on 2020 presidential candidates, such as Sens. Elizabeth Warren of Massachusetts and Bernie Sanders of Vermont, who support replacing the Affordable Care Act with Medicare for All, Pelosi replied, "I'm not for doing away with Obamacare."

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