Process systems engineering is rapidly moving from steady state simulation towards operator training simulation, based on dynamic models, automated procedures, and predictive systems. Conventionaloperating conditions are well-known and easily controlled by field operators as well as control-roomoperators, whereas other situations are not yet. This is the case of more unusual circumstances, such as plant start-ups as well as planned and emergency shutdowns. The implementation of detailed dynamic mathematical models allows simulating the behavior of single process units as well as industrial plants, with the possibility to study unusual scenarios, especially for two reasons. First of all, it is necessary to train the operator and prepare him/her to face several events. Secondly, there is the need for evaluating the best automatic procedure to manage either unconventional or critical situations, without waiting for them to occur. In this sense, the safety approach is changing from reacting to predicting, thanks to the spread of tools that offer the possibility to simulate accidental events, unit and/or valve malfunctions, and significant process transients. The paper investigates and compares different procedures to controlprocess transients, described by a sequence of actions, in order to coordinate synergistically the actions dictated by control-room operators and the operations to be accomplished manually by fieldoperators. The main objective is to improve process start-up and shutdown reliability as well as the corresponding plant safety of an existing plant-wide control structure, without requiring any structural modification. A propane/butane splitter is adopted as a case study.