A divided D.C. Court of Appeals reversed itself yesterday and ruled that the city's elections board can go ahead with its plan to allow persons who are not listed on the voter rolls and have no proof of registration to cast regular, unchallenged ballots on Tuesday, just like voters whose registration is recorded.

The decision means that persons whose names are not on voter lists at the city's 137 precinct polling places and who do not present registration cards will be allowed to cast regular ballots if they show suitable identification, such as a driver's license, and sign an affidavit that they are properly registered.

In the Sept. 14 primary, some 20,000 registered voters were forced to cast special, challenged ballots that were counted only after being certified by the elections board, because their names did not appear on the voter rolls. The elections board decided to institute the new voting procedure in response to public outcry over the widespread confusion in the primary.

The court had ruled on Friday, in response to a suit filed by Ward 5 Republican city council candidate W. Ronald Evans, that the new procedures could not be used unless the board could show they were absolutely necessary.

Evans' attorney, Melvin M. Burton Jr., said that Evans would not appeal the ruling to the full nine-member appeals court. "It would not be fair to leave the public in an eleventh-hour state of confusion," Burton said.

Under the new procedure, which was proposed by the elections board's acting executive director, David Splitt, the votes of those who are not on the rolls but who present identification that shows they are residents of the precinct and sign affadavits will be counted immediately.

The votes of those who are not on the rolls but who present registration or notification cards also will be counted immediately.

Those who do not have sufficient identification will be allowed to cast special, challenged ballots.

Splitt said that all of the affidavits would be checked after the election and the board would take steps to prosecute anyone who signs a false affidavit.

The penalty for voter fraud is up to five years in prison and a $10,000 fine.

After the court's ruling Friday Splitt argued in an affadavit to the court that the new procedures were necessary for the election to run smoothly, and defended their hasty implementation on the ground that there was not enough time to schedule public hearings on the matter.

The affidavit satisfied a majority of the three-judge panel.

But, in a strong dissent, Judge John W. Kern III said he was "not persuaded that the eve-of-election" changes were necessary.

"To me, this last-minute board action only complicates a long-standing situation of confusion and errant administration," Kern said. "I would agree with Evans that the integrity of the election requires a stay of this last-minute monkeying with the machinery."

The judges issued their ruling after an unusual Saturday telephone conference call in which judges Catherine B. Kelly and John M. Ferren voted, based on Splitt's response, to reverse their earlier decision.

Evans and other critics of the new procedures maintained that they would leave the election open to voter fraud. Evans pointed out that the city's voter rolls currently contain perhaps as many as 70,000 names that are duplicates or the names of residents who have died or moved from the city.

In a prepared statement, Evans urged voters to "remain alert and vigilant for acts of impropriety" on election day.

Elections board officials, who say they do not anticipate vote fraud, said yesterday that they are not certain how many voters will be affected by the new procedures.

Splitt said that the names of "99 percent" of all voters who had to cast challenged ballots in September are now on precinct rolls.

He estimated that the number of people who would be voting by showing a registration card or signing an affidavit because their names are not on the voter lists would be, "maybe a thousand."