The structural relations established among agents has influence on the performance of decentralized service discovery process in Multi-Agent Systems (MAS). Moreover, distributed systems should be able to adapt their structural relations to changes in environment conditions. In this paper, we present a Service-Oriented MAS where agents initially self-organize their structural relations based on the similarity of their services. Agents integrate a mechanism that during the service discovery process facilitates the self-organization of their structural relations in order to adapt the structure of the system to the service demand. This mechanism facilitates the task of decentralized service discovery and improves its performance. Each agent has local knowledge about its direct neighbors and the queries received during discovery processes. With this information, an agent is able to analyze its structural relations and decide when it is more appropriate to modify its direct neighbors and select the most suitable acquaintances to replace them. The experimental evaluation shows how this self-organization mechanism improves the overall performance of the service discovery process in the system when service demand changes.