An article on yesterday's Federal Page incorrectly described a remark as a paraphrase of Rudyard Kipling. The lines referred to -- "Theirs not to make reply,/ Theirs not to reason why,/ Theirs but to do and die" -- are from "The Charge of the Light Brigade" by Alfred, Lord Tennyson.

On his first day as acting administrator of the Small Business Administration, Charles L. Heatherly yesterday fired half the agency's 10 regional administrators, ordering them to vacate offices by the close of the day's business.

Spokesman Rick Utley said Heatherly "wants his own people in there; he wanted to get people who were supportive and who would aggressively support the president's position" on the SBA.

President Reagan has proposed to eliminate SBA loan programs and transfer many of the remaining functions of the agency to the Commerce Department. The previous administrator, James C. Sanders, fought the plan.

John J. Motley, director of federal legislation for the National Federation of Independent Business, called the firings "a dirty trick on the small business community, conducted while Congress is out of session by an acting administrator who doesn't have to account for his actions."

At the request of the White House, Sanders named Heatherly deputy SBA director last week. When Sanders left office, Heatherly automatically became acting director. His name has not been submitted for Senate confirmation "to my knowledge," Utley said. Small business lobbyists accuse the administration of circumventing a confirmation fight.

The regional administrators in Boston, San Francisco, Philadelphia, Dallas and Denver were called by the SBA personnel director starting at 9 a.m. yesterday and told they were fired immediately, according to Utley. They will remain on the payroll for 30 days while they look for work.

"Welcome to the April Fool's Day Massacre," said a somber Carlos R. Suarez, administrator of SBA's Region 8, as he wearily packed boxes yesterday afternoon in his Denver office.

"I'm a political appointee," Suarez said. "I serve at the pleasure of the president. But this was -- well, brutal is a fair word to use."

Suarez has been regional administrator for 4 1/2 years. He said he has been engaged for a year or more in the "delicate business" of running a government operation while preparing for its possible demise. If the decision had been made to close the agency, he said, "I would have helped move to an orderly shutdown."

"In my position, it's ours not to reason why, ours not to make reply, ours but to do and die," he added, in a paraphrase of writer Rudyard Kipling. "And today -- I'm dying."

Regional officials said Heatherly called the administrators in other regions and told them they were safe "for the time being."

Heatherly has been director of the President's Commission on White House Fellowships, served at the Department of Education and was director of special projects at the conservative Heritage Foundation from 1979 to 1981.

Rep. Parren J. Mitchell (D-Md.), chairman of the Committee on Small Business, asked Heatherly in a telegram to rescind the firings, according to an aide, calling the firings a "wrong decision." And Rep. Norman Y. Mineta (D-Calif.) also sent a telegram, calling the move "unconscionable," according to an aide.