This study traces the development of the management accountant (MA) role at the Swedish Social Insurance Agency (SIA). In 2012, the agency began a reformation by implementing the Lean management system in hopes of increasing customer trust. The results of this study show that the authority of the MA rests on decentralization and the proximity of MAs to managers, as previous research has shown, and more specifically on a definitional and a moral prerogative that may or may not be awarded to MAs enabling them to act as de facto managers. The study shows how the role of the SIA's operative level MAs changed into a helpdesk function with the role of assisting other groups to help themselves, in this case operative-level teams that had begun performing management accounting tasks. Thus, this study bears witness not to the expansion and hybridization of existing MA roles, but to the reduction in authority and de-hybridization of the MA role, from business partner to a pedagogical role on a consultative basis.