When modelling knowledge of multiple experts, it is interesting to build a common expertise model corresponding to the kernel of knowledge common to the experts. Therefore the expertise conflicts between the expertise models of the different experts must be tackled. The domain level of an expertise model can be described through concepts linked by relations, and represented through Sowa's conceptual graph formalism. This report presents a method for conflict management during knowledge modelling from multiple experts: this method relies on the comparison and integration of several conceptual graphs corresponding to different viewpoints, the integration being guided by different integration strategies. For the comparison of the conceptual graphs, we define and exploit possible relations that can link such graphs. The appendix presents a base of conceptual graphs obtained by modelling the knowledge of several experts in traffic accident analysis.