This research aims to analyze the indirect and asynchronous interaction between a designer of online resources managed in a training scenario and the teacher who implements them in the context of teacher training. From theoretical considerations about the instrumental genesis of the artifact and the appropriation of resources, we try to characterize appropriation processes through a threshold which means that appropriation is done without misappropriating the design goal of resources and scenario. This study focuses on a French national blended learning program (Pairform@nce) based on a collaborative training. More specifically, we tend to highlight modifications, additions and suppressions of resources as well as modifications of scenario and use of supports as indicators of appropriation.These indicators are proposed from the analysis of four interviews with trainers and then verified by reading logbook of other trainers. Results from the analysis lead us to propose a collaborative tool for improving asynchronous interaction between designer and teacher.