Mall owner General Growth said on Wednesday it has replaced some of its managers, in a sign that its focus has switched from exiting bankruptcy to beefing up operations.

They're moving from defense to offense, Sandler O'Neil analyst Alexander Goldfarb said.

The Chicago-based company has named Michael McNaughton, currently senior vice president of leasing-Big Box, as head of asset management. McNaughton, who joined the company in 2001, will replace Sharon Polonia.

Vice Chairman Robert Michaels has been named head of leasing and replaces Robert Wyant. He started at General Growth in 1972 and has served in a number of senior management roles, including general counsel and executive vice president and director of corporate leasing.

Mark Pfeifer, vice president of strategic communications, has been named head of marketing and corporate communications. He joined General Growth in 2002 as vice president of corporate advertising and branding and later became vice president of strategic communications. He replaces Wally Brewster.

General Growth has submitted a plan to emerge as a stand-alone company bankrolled by $7 billion from Brookfield Asset Management , Fairholme Capital Management and Pershing Square Capital Management. It has spurned a sweetened takeover offer from larger rival Simon Property Group Inc . It is open to bids from other potential capital sources and suitors, and is scheduled to present a final plan to the bankruptcy court by the first part of July.

Shares of General Growth closed down 3.3 percent, or 46 cents, at $13.42 on the New York Stock Exchange, underperforming the benchmark MSCI U.S. REIT Index <.RMZ>, which was off 1 percent.

(Reporting by Ilaina Jonas; Editing by Richard Chang)