German media conglomerate

Bertelsmann

shook up the management of its

BMG Entertainment

unit Sunday, saying the unit's head and an executive board member would resign at year-end.

Bertelsmann said Strauss Zelnick, BMG Entertainment's president and CEO, and Michael Dornemann, executive board member in charge of BMG Entertainment, would step down Dec. 31. The company said the resignations would "facilitate the restructuring of Bertelsmann's television, music and new media divisions and allow for a swift transition." Dornemann will remain the unit's chairman through June 30.

Dornemann has been with Bertelsmann for 18 years, including 16 years as an active member of the executive board. Zelnick joined BMG in January 1995 as president and CEO of the company's North American business unit and was named president and CEO of BMG Entertainment in July 1998.