The rumors were true: Pandora CEO Tim Westergren has announced that he's stepping down from the company he co-founded 17 years ago. He'll remain in the leadership position while the company searches for a replacement. President Mike Herring and marketing chief Nick Bartle are also leaving, the streaming music company says. While Pandora isn't clear about why the executives are bowing out, it comes after efforts to "refocus and reinforce" the firm by selling its ticket business and taking a $480 million cash infusion from SiriusXM. In other words, it's likely looking for fresh blood as it adapts to a changing digital music landscape.