The Massachusetts Senate passed a bill Thursday calling for revisions to the state voter-approved recreational marijuana law, setting the stage for negotiations with the House, which just a day earlier backed a more far-reaching overhaul.

The debate in the Senate over the reshaping of the law which allows adults to possess up to 1 ounce of marijuana and grow up to 12 pot plants per household focused mostly on regulatory matters. It unfolded after the House angered many supporters of legalized marijuana by voting to repeal the existing law and replace it with a measure that would, among other things, raise the tax rate on marijuana from 12 percent to 28 percent.

The Senate bill, approved on a 30-5 vote, would keep the current measure in place but with proposed changes in the way both recreational and medical marijuana would be overseen by the state.

"We should not repeal and replace ... we should amend and improve," said Sen. Patricia Jehlen, co-chair of the Legislature's Marijuana Policy Committee, at the outset of debate. "That is what this bill will do."

"We need to try to restore some trust in government by not overriding the will of the people," added the Somerville Democrat, a veiled reference to criticism leveled at the House bill by pro-marijuana activists.

The next step will be naming a conference committee made up of three senators and three representatives that will attempt to reach a compromise. Legislative leaders self-imposed a July 1 deadline to deliver a bill to Republican Gov. Charlie Baker's desk, acknowledging that further delays would jeopardize the planned July 1, 2018 start of retail marijuana sales.

The Senate bill holds the tax rate at a maximum of 12 percent, as approved by voters. Keeping taxes relatively low, Jehlen said, would entice consumers to buy pot from legal suppliers, while a higher tax might persuade them to continue purchasing from an illegal dealer or perhaps even drive to Maine, where recreational marijuana will be taxed at 10 percent.

The House and Senate bills both change the structure of the Cannabis Control Commission, the state agency that will regulate marijuana. The ballot question called for a three-member panel appointed by the state treasurer, while lawmakers want a five-person board consisting of members named by the treasurer, attorney general and governor.

A key difference, however, is while the House envisions all five commissioners working full-time at their jobs, under the Senate bill only the chairman of the panel would be full-time and the others unpaid volunteers.

Sen. Jason Lewis, a Winchester Democrat who opposed marijuana legalization, promised to support the Senate bill but sought assurances that the cannabis industry would not become dominated by large national companies.

"We don't want to see big marijuana like we have big tobacco or big alcohol," said Lewis, who joined other lawmakers in calling for programs that encouraged women, minorities, veterans and small farmers to own or find employment in legal marijuana businesses.

Senators adopted several amendments before the final vote Thursday night, including one that would make it easier for people to erase past convictions for possessing amounts of marijuana that are now legal in Massachusetts.