In this paper, we examine the experience and results from a project conducted by a university team that partnered with an advanced citizen group in Santiago, Chile, as part of a key phase in a multi-year process of change. Interest arose in response to local advocacy and was significantly mobilized through a three-year collaborative planning process led by the regional government and citizens' groups, with technical assistance from Dutch experts. The experience discussed here reveals that it was the ongoing iterations between different kinds of technical and non-technical actors and the resulting blend of urban expertise that drove the process forward, leading to systemic changes in both planning and city spheres. (C) 2015 Elsevier Ltd. All rights reserved.