In a big change to its retail brokerage leadership, Morgan Stanley announced it is naming Greg Fleming president of global wealth management, replacing Charlie Johnston.

First reported by Bloomberg, the move comes as Morgan Stanley Smith Barney continues to integrate the joint venture that was announced in January 2009. The story was confirmed by a Morgan Stanley spokesperson.

According to the internal memo obtained by On Wall Street, Morgan Stanley’s president and chief executive officer James Gorman said: “Charlie Johnston has informed me of his desire to retire from the firm at the end of 2011 and spend more time on family and charitable pursuits. . . Charlie believes it is the right time to make this change.”

Johnston will become vice chairman of Morgan Stanley Smith Barney for the next year, according to the memo.

Fleming, who the memo said would become president of global wealth management, currently runs the firm’s asset management business. He will continue to handle those responsibilities, according to the memo.

“I am confident that under Greg's ongoing leadership of MSIM, we will continue to see tangible progress toward our goal of building a leading asset management business,” Gorman said in the memo. “I believe Greg is also ideally suited now to build on the tremendous momentum in our wealth management business.  He brings vast experience and a proven record of leadership to this role.”