Gisele Grayson

Updated at 8:15 p.m. ET

The Republican's seven year quest to repeal and replace the Affordable Care Act descended into chaos Thursday night as the Senate prepared for an unwieldy, all-night session.

Updated July 25, 5:25 PM ET: Tuesday afternoon, the Senate voted to send the original House legislation repealing and replacing the Affordable Care Act to the floor. (Details below on the proposals/bills.)

But the Senate is only using it as a vehicle to add amendments that will change it substantially. The first amendment would phase out many of the Affordable Care Act's provisions over two years.

The GOP's latest proposal to repeal and replace the Affordable Care Act hews closely to the earlier bill that didn't win enough support among lawmakers to bring to a vote.

Perhaps the biggest change in the document released Thursday is that it leaves in place the Affordable Care Act taxes on wealthy individuals. It uses that money to reduce the number of people left without insurance coverage by the law's changes. This latest version adds $70 billion to a fund for states — bringing the total to $132 billion — to help support coverage of low-income people.

The nonpartisan Congressional Budget Office weighed in on the Senate health care bill on Monday, saying that 22 million people would lose health coverage in the next 10 years under the Senate's plan. Of those, 15 million would lose Medicaid coverage. It's projected to lower the deficit by billions over 10 years, and also cut taxes on corporations and the wealthy.

Senate Republicans on Thursday unveiled their plan to repeal and replace the Affordable Care Act — also known as Obamacare. The long-awaited plan marks a big step toward achieving one of the Republican Party's major goals.