This article investigates the interactional constitution of a phenomenon recurrently reported by teachers who complain about a loss of authority, a systematic delegitimization of their role. Adopting a conversation analysis informed approach to a single-case study from a corpus of parent-teacher conferences, we illustrate how challenging the teachers' expertise is accomplished by participants as an outcome of some identifiable communicative practices. Particularly, we analyze the practices of "quoting" and "referring to the expert" as interactional resources differently exploited by participants: While parents challenge the teachers' epistemic authority and lay the foundation for claiming the right to decide what do to with their son in the classroom, teachers contribute to this epistemic positioning and cede their expert knowledge-based deontic rights, that is, the right to decide the best practices to adopt in the classroom. In the discussion, we advance that the participants' interactive competence in navigating the complex epistemic landscape of the encounter profoundly impacts on the local definition of reciprocal epistemic and deontic rights and responsibilities. Indications for teachers' education are provided in the conclusion.