A method, a system and a processing device for simultaneous manual retooling of at least two units or for simultaneous exchange of at least two format parts within a processing device. The processing device includes at least two working areas, each including a retooling area, a working opening and an activation device. The working openings exist in an open retooling state or in a closed processing state. For retooling at least two of the working openings are opened. The actual state of the working openings of at least two working areas is determined. Furthermore the activation of at least one activation device is recognized. If the activation devices of open working openings are activated simultaneously, a repositioning of convertible units or format parts is triggered.