Reginald D. Johnson has been promoted to deputy auditor at Riggs National Bank, Johnson is headof international department audits and helped draft policies for Riggs' branchin London. He also helped the bank implement its computerized accounting systems.

The chairman of the board of the McLean Bank of Virginia has announced the election of three additional board directors.

They include: Frank J. Patterson, the president of Patterson & Associates, one of the largest insurance agencies here. He is also director of the Independent Insurance Agents of America and serves on the corporate board of Children's Hospital. Richard C. Scalise heads a private law firm in McLean. Henry C. Mackell is a partner of Mackall, Mackall, Walker & Silver law firm in Fairfax and serves as general counsel for McLean Bank. He is a past president of the Fairfax County Bar Association.

Stephen B. Clarkson, Charles E. Pardoe and Wilber L. Ross have been elected to board of directors of Government Services Savings and Loan Inc. eClarkson is a partner of the Sullivan & Beauregard law firm in the District; Pardoe is cofounder and vicepresident of Barnes, Morris and Pardoe Inc., commercial real estate brokers, and Ross is managing director of the New Court Securities Corp. inNew York.

A. G Edwards & Sons Inc. announced that John C. Cassidy, John L. Fish and Fred Turk are now senior investment brokers at the company's Alexandria branch.

The board of directors of Johnston, Lemon & Co. Inc., a local investment firm, has appointed Thomas T. Wallace general sales manager. He will be responsible for the sales efforts of the firm's four regional offices. With the firm since 1968, Wallace has been manager of its Bethesda office for four years.

Cabot Feldman has joined Diplomat National Bank as vice president for marketing. He held a similar position at D.C. National Bank for 12 years.

Charles P. Mahoney III has been named vice president and secretary of the Equitable Life Insurance Co.

Robert W. Irving, executive vice president for the Equitable Trust Co., has been named to the new Community Economic Development Policy Board of the American Bankers Association.