design pattern : How to manage the change state of an object that affect others ( Dynamics Ax application )

I m working in Dynamics Ax to Create a CMMS/EAM module. an equipement could be in maintenance (state = breakdown), that means its attached to a work request, the work request is accepted and a work order is create. the work order is composed of interventions that have to be finished so that the worker order is completed. i want to manage the state of these table with a classe in order to follow the Dynamics Ax best practice. i want to manage the state of these dependent table with the use of one of the design pattern. first i thought about the Observer_Subject design pattern. i designed this solution but it seems to be very complicated. any one who have any expertise in Design pattern give me an idea how could i create the best practical solution for this state of art. and an expertise in dynamics Ax is preferred. Thanks Cdt.