When we have Orchestration in the same project, we can select it directly in Called Orchestration property of the CallOrchestration shape. But when we have called orchestration in reference assembly (Another Project), we need to set the Type Modifier property of that orchestration to Public. By default it is Internal. But to use any orchestration as Referece Assembly in another project for CallOrchestration shape, we need to set its Type Modifier property to public and one more thing that the receive shape of that called orchestration must not Activated(i.e. its Activate property should be False). So an so we can find that orchstration in CallOrchestration’s reference assembly else not.