(Update: Several GOP senators have pushed  amendments to cover ‘a lot of concerns’ in the tax reform bill that has led to Republican leaders rewriting parts of the bill. The vote was postponed until at least some time on Friday. )

Senate Republicans leaders said Thursday they are confident they will have the votes to pass a bill by Friday that will offer, for the first time in 31 years, a major overhaul of the U.S. tax code.

"It's almost ready to take out of the oven," Sen. Lindsay Graham, (R-S.C.), told CNN. "We're going to get there. It's just a matter of how we get there. It's not if we get there, it's just how we get there. We're gonna get a pass. We're gonna pass this tax cut bill this week."

Sen. John McCain, (R-Ariz.), who had been a holdout, announced Thursday he would vote yes on the tax reform bill.

If it passes, the measure will give President Donald Trump a win on one of his biggest campaign promises.

The Senate bill will nearly double the standard deduction used by about 70 percent of U.S. taxpayers from $6,350 for individuals and $12,700 for married couples to $12,000 for individuals and $24,000 for couples. The bill would eliminate the personal deduction of $4,050.

Here’s what to know about when the vote is likely, who is for it and who is on the fence, and some of the fine points of the legislation.

When will the vote take place?

That is hard to tell, but it looks like it could be very late on Thursday or early on Friday. (Check back here for the latest update on the vote time).

What happens next?

The clock is now running for debate and when that clock runs out, time will be yielded back to the chairman, then a “vote-a-rama” will begin. A vote-a-rama is defined as 15 or more votes on a piece of legislation in one day. The votes come as senators introduce amendments to legislation. They can introduce unlimited amendments. Each amendment must be voted on. It can go on for some time.

How many votes are needed?

For the bill to pass, 50 votes are needed. The GOP can lose two votes, leaving the vote at 50-49, and still have the bill pass, assuming all the Democratic and Independent senators vote no.

Where does the vote stand as of Thursday afternoon?

The momentum on the bill has shifted somewhat since McCain announced his decision to vote yes. As it stands now, 42 Republicans have said they intend to vote for the bill. Ten GOP senators are still considering their vote, and all 46 Democratic and both Independent senators are planning to vote no.

Who has concerns?

These 10 senators have expressed concerns over certain parts of the bill, but have not said they will vote no.

Susan Collins (Maine)

Bob Corker (Tenn.)

Steve Daines (Mont.)

Jeff Flake (Ariz.)

Dean Heller (Nev.)

Ron Johnson (Wis.)

John Neely Kennedy (La.)

Mike Lee (Utah)

Jerry Moran (Kan.)

Marco Rubio (Fla.)

Who is in?

Forty-two GOP senators have indicated they will vote yes on the tax reform bill.

Lamar Alexander (Tenn.)

John Barrasso (Wyo.)

Roy Blunt (Mo.)

John Boozman (Ark.)

Richard Burr (N.C.)

Shelley Moore Capito (W.Va.)

Bill Cassidy (La.)

Thad Cochran (Miss.)

John Cornyn (Tex.)

Tom Cotton (Ark.)

Mike Crapo (Idaho)

Ted Cruz (Tex.)

Mike Enzi (Wyo.)

Joni Ernst (Iowa)

Deb Fischer (Neb.)

Cory Gardner (Colo.)

Lindsey O. Graham (S.C.)

Charles E. Grassley (Iowa)

Orrin G. Hatch (Utah)

John Hoeven (N.D.)

James M. Inhofe (Okla.)

Johnny Isakson (Ga.)

James Lankford (Okla.)

John McCain (Ariz.)

Mitch McConnell (Ky.)

Lisa Murkowski (Alaska)

Rand Paul (Ky.)

David Perdue (Ga.)

Rob Portman (Ohio)

James E. Risch (Idaho)

Pat Roberts (Kan.)

Mike Rounds (S.D.)

Ben Sasse (Neb.)

Tim Scott (S.C.)

Richard C. Shelby (Ala.)

Luther Strange (Ala.)

Dan Sullivan (Alaska)

John Thune (S.D.)

Thom Tillis (N.C.)

Patrick J. Toomey (Pa.)

Roger Wicker (Miss.)

Todd C. Young (Ind.)

Who is out?

Every Democratic senator, plus two Independent senators (Angus King and Bernie Sanders) who caucus with the Democrats, have indicated they will vote no on the tax reform bill.

Tammy Baldwin (Wis.)

Michael Bennet (Colo.)

Richard Blumenthal (Conn.)

Cory Booker (N.J.)

Sherrod Brown (Ohio)

Maria Cantwell (Wash.)

Ben Cardin (Md.)

Tom Carper (Del.)

Bob Casey (Pa.)

Chris Coons (Del.)

Joe Donnelly (Ind.)

Tammy Duckworth (Ill.)

Dick Durbin (Ill.)

Dianne Feinstein (Calif.)

Al Franken (Minn.)

Kirsten Gillibrand (N.Y.)

Kamala Harris (Calif.)

Maggie Hassan (N.H.)

Martin Heinrich (N.M.)

Heidi Heitkamp (N.D.)

Mazie Hirono (Hawaii)

Tim Kaine (Va.)

Angus King (I-Maine)

Amy Klobuchar (Minn.)

Patrick Leahy (Vt.)

Joe Manchin (W.Vir.)

Ed Markey (Mass.)

Catherine Cortez Masto (Nev.)

Claire McCaskill (Mo.)

Bob Menendez (N.J.)

Jeff Merkley (Ore.)

Chris Murphy (Conn.)

Patty Murray (Wash.)

Bill Nelson (Fla.)

Gary Peters (Mich.)

Jack Reed (R.I.)

Bernie Sanders (I-Vt.)

Brian Schatz (Hawaii)

Chuck Schumer (N.Y.)

Jeanne Shaheen (N.H.)

Debbie Stabenow (Mich.)

Jon Tester (Mont.)

Tom Udall (N.M.)

Chris Van Hollen (Md.)

Mark Warner (Va.)

Elizabeth Warren (Mass.)

Sheldon Whitehouse (R.I.)

Ron Wyden (Ore.)

What’s in the bill? 

From The Associated Press:

The overall package is a blend of generous tax cuts for businesses and more modest tax cuts for families and individuals.

The package would lower the corporate income tax rate from 35 percent to 20 percent, and it would allow businesses owners to deduct up to 20 percent of their business income.

The plan would nearly double the standard deduction to around $12,000 for individuals and about $24,000 for married couples. The tax cuts for individuals would expire in 2026 while the corporate tax cuts would be permanent.

What does the Senate bill mean for your taxes?

The Joint Committee on Taxation offered this analysis on how the Senate bill will affect taxpayers:

  • 61 percent of taxpayers would receive a tax cut.
  • 8 percent of taxpayers would receive a tax increase.
  • 30 percent of taxpayers would see little or no change.