In its second executive shuffle of the year, Microsoft Corp. announced on Thursday that the head of the unit which produces its valued Office software suite, plans to retire in September to be replaced by Stephen Elop, the former chief operating officer at Juniper Networks.

Raikes, head of the Business division at Microsoft and a 26 year employee, will step down from his duties at the end of January but will continue as part of Microsoft's senior leadership team until his retirement, the company said in a statement.

Earlier this week, the company announced its first significant executive departure of the year, Bruce Jaffe, the corporate vice president. Jaffe oversees Microsoft's mergers and acquisitions strategy and will leave the company in February.

Before his COO position at Juniper, Elop was previously the chief executive of Macromedia Inc., which was acquired by Adobe Systems Inc. in 2005.

Stephen brings with him a proven track record of success in a range of business and technology areas that map closely to the challenges and opportunities that lie ahead for our [business division], Microsoft Chief Executive Steve Ballmer said in a statement.

Microsoft's business division includes the valued Office software franchise and the unified communications unit which was launched last year to better focus on integrating telecommunications services with businesses' computer software and networking.

In October, Microsoft's business division reported a 21 percent increase resulting in first-quarter revenue of $4.1 billion over the same period a year earlier. This was mainly due to the success of Office 2007, a product released roughly one year ago.