The U.S. brokerage arm of UBS shook up its leadership ranks on Friday, removing a layer of management under CEO Robert McCann and giving private wealth management head Jason Chandler a bigger role.

McCann, the former Merrill Lynch executive who took over UBS Wealth Management Americas in 2009, also gave some top lieutenants more duties as he takes on his new, expanded role as chief executive of UBS Americas, according to an internal memo distributed on Friday that was obtained by Reuters.

The Swiss bank in November put McCann in charge of both its investment bank and brokerage operations in the United States. UBS globally wants its bankers, traders and fund managers to focus on activities that support the personal wealth business.

Among the most significant moves, Robert Mulholland, a fellow Merrill veteran who runs brokerage field operations, will now also be in charge of investment products and platforms.

Chandler, who has run the firm's high-net-worth business, now takes over UBS brokerage field operations across the United States as two regional divisions are eliminated. Eleven regional managers will report to Chandler.

Eastern division leader David McWilliams takes on a newly created role of "wealth management transformation," responsible for expanding the firm's relationships beyond investments to include more lending and financial planning.

Western division head Mike Schweitzer is leaving the firm.

Another key move is the elevation of Dan Cochran to chief operating officer, responsible for finance, risk, operations and technology -- essentially the day-to-day operations of the wealth management division. He replaces Anita Sands, who will now report to Cochran and focus on technology and operations.

Paula Polito, who had been chief marketing officer, also takes on a new job heading "strategic clients and partnerships," where she will lead efforts to attract more emerging affluent investors as well as corporate business and retirement services.

Brian Hull, meanwhile, was named head of strategic clients and partnerships. He plays a key role in developing relationships with colleagues within UBS investment bank and asset management, and with third parties that provide research and manage money for UBS clients, the memo said.

(Reporting By Joseph A. Giannone; Editing by Walden Siew and Gerald E. McCormick)