The research investigates the role of leadership in the transformation of denominational structures towards a missional ecclesiology, and focusses on the Highveld Synod of the Dutch Reformed Church. It describes the missional journey of the denomination, and interprets the transformation. The theory of 'complex leadership' in complex systems is applied to the investigation of the impact of leadership on a denominational structure. The theory identifies three mechanisms used by leaders as enablers in emergent, self-organisation systems: (1) Leaders disrupt existing patterns, (2) they encourage novelty, and (3) they act as sensemakers. These insights are applied as a tool to interpret the missional transformation of a denomination.