This article develops an account of the discourse updates contributed by utterances of declarative sentences with the Cuzco Quechua reportative. The challenge posed by such utterances is that the speaker does not need to be committed to the at-issue proposition f and may even deny its truth. They are therefore not assertions. Yet f can behave in many ways like an asserted proposition in discourse:it can be used to answer questions, link to the discourse with veridical rhetorical relations, and, if accepted by the interlocutors, be subsequently presupposed. The proposed semantics for the reportative assigns the commitment to f to a third-party principal instead of to the discourse participant producing the utterance, leaving them free to disagree with f. However, if they do not disagree, they will be understood as intending to propose it to the common ground. This, it is argued, is due to the Collaborative Principle, a pragmatic principle that requires discourse participants to provide evidence of any discrepancy in commitments. The analysis is implemented in a modified version of the discourse framework of Farkas & Bruce 2010.