REDMOND, Wash. -- Microsoft Corp. today announced changes to its organizational structure. Under the new structure, the leaders of each of the company's core businesses -- Windows® Client, Knowledge Worker, Server & Tools, Business Solutions, CE/Mobility, MSN® and Home & Entertainment -- will have comprehensive operational and financial responsibility and greater accountability. As part of these changes, Rick Belluzzo will transition out of his role as president and chief operating officer on May 1, although he will continue to work at the company through September to ensure a smooth transition.