Washington (CNN) If Republicans want to try again to repeal the Affordable Care Act with just a simple majority, they only have until the end of September to do it.

That's according to Sen. Bernie Sanders, the ranking member on the Senate's budget committee. According to Sanders, the Senate parliamentarian declared Friday that the Senate's 2017 budget resolution, which gave reconciliation instructions to repeal Obamacare, will expire at the end of the month.

That means that Republican senators will either have to pass a new budget to repeal health care with a simple majority or they will have to have 60 votes -- a filibuster-proof majority -- to make changes to Obamacare.

The parliamentarian's office declined to comment to CNN, saying its policy was not to speak with the media. CNN has reached out to Republicans on the Senate budget committee about whether they agree with Sanders' assessment.

"Today's determination by the Senate parliamentarian is a major victory for the American people and everyone who fought against President Trump's attempt to take away health care from up to 32 million people," Sanders said in a statement. "Now that the parliamentarian has determined that Senate Republicans cannot use reconciliation instructions to repeal the Affordable Care Act beyond this fiscal year, we need to work together to expand, not cut, health care for millions of Americans who desperately need it."

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