Based on a multiple case study on Service Design (SD) projects, we discuss different levels of SD's transformative impacts, associated with three types of designer-client relationships. In the 'delivering' relationship, SD informs service planning and development practices based on user-centred insights, while affecting physical service resources/technologies. In the 'partnering' relationship, SD aligns actors with the target users' experience while extending the SD impact, beyond physical resources/technologies, to human actors. Finally, in the 'facilitating' relationship, SD helps client organisations build their own capabilities for sustainable user-centred innovation, while achieving a wider impact on physical resources/technologies, hu...