Mayor Marion Barry said yesterday that he will soon make changes in the leadership of the city's rent control office that are expected to include the firing of its administrator, Bowles C. Ford.

Barry volunteered his plans to shake up the Rental Accommodations Office during his first meeting with members of the city's 36 advisory neighborhood commissions.

During the two-hour session, Barry refused a plea that he support a near total moratorium on condominium conversions, declaring that such a statement by him would backfire. He said he would soon present a plan to slow the trend.

Barry did not say flatly that he would fire the 37-year-old Ford.But a Barry aide, who asked not to be quoted by name, said Ford is on his way out after two years as head of the rental office because he provided sluggish leadership and delayed a general rent increase for the city's landlords by seven months.

Ford, reached at home, said he had heard rumors earlier last week that he might be fired, "but I could get no confirmation from anybody."

The mayor "has every right to get rid of me," Ford said. But on the question of the general rent increases, Ford said, "the mayor and his aides are confusing the [Rental Accommodations] Office with the [Rental Accommodations] Commission.

Although they have similar names and have related functions, Ford said they are entirely separate and even have different staffs. The commission sets policy and adjudicates issues, while the office administers, he said.

Under the city's rent control law, the commission was supposed to recommend the level of this year's general rent increase by last Nov. 15, but did not vote until March 4.Increases up to 9.4 percent are now scheduled to start going into effect June 1.

Since taking office Jan. 2, Barry has replaced about a dozen department and agency heads he regarded as incompetentt or unresponsive. Of the rental office, he said yesterday, there would possibly be a new administrator and "if that captain doesn't work, we're going to get another captain."

Barry's two-hour meeting at the Georgetown University Law Center with about one-third of the city's 360 elected ANC members had an agenda with 15 items covering the spectrum of city problems.

But the ANC members carried out their role as grass-roots neighborhood spokesmen by using almost all the time complaining about poor trash collection and condominium conversions.

Hank Larson of Ward 4 in the far upper Northwest had a typical complaint. There is an "atrocious" situation at Georgia Avenue and Quackenbos Street NW, he said, where a city trash can always spills its contents because the pickup crew refuses to take a few moments to replace a long-broken liner.

Herbert L. Tucker, the city's environmental services director and one of three dozen city officials at the meeting, promised prompt action on this and all the other complaints he heard.

Most of Barry's personal fielding of questions dealt with condominium conversions.

Leroy Harris of Ward 5 in the near Northeast told the mayor in an emotional speech that he wanted them banned altogether. Robert Love of Ward 1, north of downtown, citing a trend toward almost-total conversion of rental apartments in Adams-Morgan, asked that the mayor endorse a halt to all such shifts except when instituted by tenants.

The mayor refused."if we telegraph our punches, with the media being here, we will have 6,000 (conversion) applications on Monday," Barry said. "i don't want that."

Barry said that on April 9, when the City Council was expected to consider an emergency bill invoking a total moratorium, landlords flocked in with applications to convert 3,000 apartment units into condominiums. The bill was not considered.

Ann Loikow of Ward 2 (downtown) said this was a case of landlords "applying for insurance," so they could convert if they could not get rent increases big enough to satisfy them. (The city approved applications for converting 10,481 rental units last year.)

Calling the situation serious, Barry said his aides are working with City Councill members on a bill to slow the conversion trend. He offered no details.

When the meeting ended, those attending went to the law center's patio for fried chicken and cola. CAPTION: Picture, Mayor Marion Barry, at microphone, with housing director Robert Moore, meets with advisory neighborhood commissioners at Georgetown University Law Center. Other department heads attended. By Vanessa R. Barnes-The Washington Post