Architects have recommended several changes in a multimillion-dollar plan for renovating historic Union Station in an attempt to gain approval from District and federal preservation officials.

The revised plans, which won a preliminary endorsement yesterday from the city's historic preservation agency, include smaller mezzanines than previously had been suggested along with elimination of some kiosks and other controversial structures that had been proposed inside the railroad terminal.

Officials said the shifts were designed to provide a relatively unobstructed view of the building's arched ceilings and other architectural features. The D.C. Historic Preservation Review Board said the revisions "should eliminate or satisfactorily mitigate potential adverse effects associated with the project."

The building, which has been closed since 1981 because of leaks in its roof and other deterioration, is to be overhauled at a cost of nearly $140 million in federal and private funds. The renovation is expected to be completed by mid-1987.

The architectural plans, drawn up largely by the Cambridge, Mass., firm of Benjamin Thompson & Associates Inc., call for extensive changes inside the building but would preserve its exterior. The three-block-long structure would contain shops, restaurants and movie theaters along with railroad facilities.

The revised plans are to be reviewed by the federal Advisory Council on Historic Preservation and other agencies before renovation work begins.

Preservation officials previously had criticized the initial plans, contending that they placed too much emphasis on commercial development and too little on preserving the building's architectural character. They urged developers to "avoid trivializing" the structure, which was constructed in 1907.

Yesterday, a staff memo made public at the city board's meeting described the proposed revisions as "a significant improvement." It said the design is "much more open" and "much more compatible with the architectural character" of the building.

In the main hall, the architects recommended dropping an earlier proposal for four commercial kiosks and replacing them with one circular structure to provide train information.