This paper presents initial work that will enable an agent to augment its ontology to incorporate required knowledge from other agents, in order to let it answer domain related queries. Speci?cally, our agents are heterogeneous, whereby an agent has its own interest domain and represents this with an ontology that contains relevant conceptualisations. These agents have intersecting domain interests and their ontologies represent a set of overlapping concepts with alternative symbolic representations. In this setting, our proposed approach focuses on reducing the costs associated with acquiring knowledge through collaboration, and augmenting axioms into an agent?s ontology. In order to achieve this, we consider incorporating knowledge to reduce the number of messages required to answer repetitive domain related queries that require mediation, and select a shared set of axioms that represent conceptual knowledge. We present results from our approach and identify the number of messages and axioms required for a repeated transaction. These preliminary results show that augmenting an agent?s ontology can indeed reduce the number of messages and axioms required.