This case study of New Zealand teachers' thinking and learning focuses on the relationship between theory and practice for teachers who become agents of change in their contexts, improving teaching and learning for students from diverse linguistic and cultural backgrounds. We rewrote an assignment for the primary and secondary teachers who taught full time and studied part time with us in a graduate TESOL programme. The task was inspired by Sannino's analysis of a critical conversation to trigger the design of an action plan that would configure richer language learning opportunities within the teachers' schools. The findings reveal the areas for action identified and the resources and tools on which the teachers drew. We drew on Kumaravadivelu's postmodern pedagogical framework with its three operating principles of particularity, practicality and possibility to analyse the findings.