Mr. Bach is expected to be given the authority to push for a range of changes, such as setting up a team focused solely on digital music, reorganizing product groups, or acquiring companies, the people familiar with the matter say. Mr. Bach's new role will add to his current responsibilities as co-chairman of an executive committee that steers consumer strategy. One immediate mission for him will be to make Microsoft's new Xbox a hub for handling digital music. A Microsoft spokesman says it is too early to discuss Mr. Bach's new role.