Goldman Sachs Group agreed to change its board structure in order to persuade a union pension fund to drop a shareholder proposal that could have cost Chief Executive Lloyd C. Blankfein his job as chairman. The deal between the New York securities firm and the American Federation of State, County and Municipal Employees (AFSCME) means Goldman will appoint a "lead" director, but shareholders will not get a chance to vote at the firm's annual meeting in May on the proposal to replace Blankfein with an independent chairman. The union had claimed stripping Blankfein of his chairman powers would help Goldman repair its reputation and reduce the potential for conflicts of interest. Goldman shareholders voted down a similar proposal in 2010 by a wide margin. AFSCME has submitted similar shareholder proposals to split the chairman and CEO duties at JPMorgan Chase & Co., American Express, Northern Trust and six other companies.