Delano E. Lewis, an executive at C&P Telephone Co., is to begin a one-year term today as president of the Greater Washington Board of Trade. Lewis thus becomes the first black to head metropolitan Washington's largest and most influential business largest and most influential advocacy organization.

Lewis had been president-elect of the board last year, so his elevation to the top leadership post in 1988 is a formality in the organization's traditional elective process. The change in the board's leadership is nonetheless a turning point in the history of the 99-year-old organization. It is at the same time a milestone for minorities in Washington's business community.

Many of Washington's business leaders will no doubt cite Lewis' election as proof of a significant shift in attitudes in the area's private sector, where minorities still encounter difficulty in ascending the corporate ladder. Choosing a black as president of the Board of Trade is hardly representative of change in the organization's 1,400 member firms, however. Indeed, the corporate responsibility and affirmative action commitments of member organizations pale by comparison.

Lewis' elevation to the presidency of the area's regional chamber of commerce is indicative of significant shifts in attitudes within the Board of Trade. Those changes didn't just occur overnight. To its credit, the board had previously elected two blacks to the office of president since 1980. But both Flaxie M. Pinkett, president of a Washington real estate firm, and Roger R. Blunt, chief executive of a local construction company, withdrew for personal reasons before their terms were scheduled to begin.

The board's philosophical and social metamorphosis was inevitable, but three factors accelerated change in the organization: the gradual development of an enlightened leadership and professional staff, a membership made more diverse in the past two decades by an influx of newcomers to Washington's business community and the dramatic shift in political power in the District to black elected officials.

Despite their apparent support of board policies, many member firms and individual members ironically haven't been nearly as aggressive in developing leadership among minorities in their own companies. Except at minority-owned firms, no Washington area company affiliated with the Board of Trade has a black president or chief executive. Few of those companies can honestly claim to have a member of a minority who is seriously being considered for promotion to a top executive position.

A 1984 study for the Greater Washington Research Center concluded that some area residents, especially college-trained blacks and women seeking professional and executive positions, are "underutilized." Little has changed since.

Lewis' election as president of the Board of Trade cuts two ways. Even though it may be seen as a symbol of change, it is above all a vote of confidence by Lewis' peers in his ability to lead the organization and set the agenda for the business community's involvement in legislative and community affairs.

At the same time, the board's decision to make Lewis its president this year raises a question about the readiness of its members to elevate qualified minorities to top executive positions and, indeed, appoint them to the boards of their respective companies.

The organizers of a new Washington banking firm have provided at least one answer to that question. When the new City National Bank of Washington receives federal approval to open this year, its chairman will be none other than Lewis, making him the first black to hold that title at a nonminority bank in the District.

0 C. James Nelson, City National Bank's president and chairman of its holding company, City National Bancorporation, attributes Lewis' selection as chairman of the bank to the high regard organizers have for him as a professional and for his knowledge of banking. Lewis was a director and chairman of the audit committee at National Bank of Washington while Nelson was its president. He also was a member of NBW's loan committee and "made a great contribution" to the bank's board, Nelson recalled.

Nelson concedes Lewis' appointment as chairman of the new bank -- not a management staff position -- is without precedent in Washington's banking industry. But the decision "has nothing to do with color," Nelson insists. "If it is a first, it is a coincidence and a nice coincidence. ... I have a very high regard for {Lewis} personally and professionally."

Much the same has been said by many of Washington's business leaders about other equally qualified professionals and executives who happen to be minorities. The difference is that the Board of Trade and Nelson and his associates have added substance to those declarations.