a system of managing collaborative session control when controller is lost or changes to passive - control mode in a data communication network comprising of a control - capable terminal device that can generate and send user preferences on successive controller selection and control policy , a master server device that can make control transfer decisions or take over control upon events , a normal terminal device that can process and response to master server queries on control capacity and its willingness to take over control . these apparatus are connected to each other inside one collaborative session , regardless of their subscriptions . a method of control management of the collaborative session without constant enrollment of controller comprises the steps of sending different types of preferences to master server device ; making control transfer or handover decision ; and interacting with affected terminals .