WASHINGTON — Republican leaders agreed to make several substantive changes to their debt limit increase measure in the wee hours of Wednesday morning as they worked to lock down wavering GOP lawmakers for the expected partyline vote later this week.

The House Rules Committee backed a rule for floor debate that would “self-execute” revisions offered in a three-page manager’s amendment from the bill’s lead sponsor, House Budget Chairman Jodey C. Arrington, R-Texas, that was submitted after midnight.

Among other changes, the measure would restore three tax credits backed by Midwestern biofuels supporters and speed up implementation of expanded work requirements for two key federal benefit programs.

It wasn’t immediately clear whether the revisions would be enough to win over the votes GOP leaders need, however. The floor schedule for Wednesday released by House Majority Leader Steve Scalise, R-La., didn’t list the debt limit package. It did, however, note that “additional legislative items are possible” during the day.

Members of the House GOP Conference are expected to discuss the measure during a closed-door meeting Wednesday morning.

The Rules Committee had been in recess for several hours while GOP leaders negotiated with holdouts into the evening on Tuesday. Rules reconvened a little before 2 a.m. on Wednesday, after a markup that began at 4 p.m. the previous day.

The panel’s ranking member, Jim McGovern, D-Mass., called the changes a result of Republicans’ “midnight séance” with their own members to come up with the necessary 218 votes for passage. The revised version is “even more draconian, even more devastating” than the initial package unveiled last week by GOP leaders, he said.

“Your problem with this bill was that it didn’t screw people fast enough,” McGovern said early Wednesday.

Republican leaders for days had sworn they wouldn’t change the text of the earlier bill to secure more votes. But after a round of meetings and whip checks, it became apparent the votes weren’t there.

Arrington’s manager’s amendment, which would be incorporated into the underlying text upon adoption of the rule, would do the following: — Restore biofuels credits: Tax credits for carbon capture and sequestration projects, biodiesel blending and “second generation” biofuels that are made from the inedible parts of crops like corn, which is the main feedstock in ethanol, would be left alone under the manager’s amendment instead of repealed as the earlier bill would do. The credits were enacted as part of Democrats’ 2022 climate and health care budget reconciliation law.

— Grandfather clause: Two other credits backed by the biofuels industry would still be repealed under Arrington’s amendment — a new incentive for “sustainable” aviation fuel and a technology-neutral “clean fuels” credit expected to benefit ethanol and biodiesel producers starting in 2025. But now there would be a transition rule that grandfathers in binding written contracts or other “concrete investment action” related to the credits that were in place between Aug. 26, 2022, and April 19, 2023, the date of the underlying bill’s introduction.

— Faster work rules: The changes wouldn’t toughen up new Medicaid work requirements, as some conservatives wanted. But it would move up the effective date by a year, to Oct. 1, 2024, for stiffer work rules impacting Temporary Assistance for Needy Families and Supplemental Nutrition Assistance Program beneficiaries. And it would add to the food stamp program’s “declaration of policy” new language stating that another purpose of SNAP is to assist low-income adults in obtaining employment and increasing their earnings, which will in turn help them purchase healthier food.

— More spending rescissions: The changes would claw back more unobligated balances of federal funding. Unspent money appropriated in the 2022 reconciliation package to repurpose older power plants and oil and gas facilities that have ceased operations, finance a new “neighborhood access and equity grant program” for disadvantaged communities and more would be rescinded under the Arrington amendment.