Pivot in regard to a product strategy means to alter the overall goal, aim, or outcome. A structured approach, this readjustment is normally initiated when it is identified that a strategy is not effective or is no longer viable. The requirement for such a change can be a result of anything from a profound shift in the marketplace, to an unexpected reallocation of resources.
When recognizing that a strategic change is needed, it is important for the product manager to engage the development team, not just by rallying them and providing new focus, but also making sure that the new direction is maintained and all available resources are realized.