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eROSITA is performing multiple all-sky X-ray surveys until 2023 comma and our team is systematically identifying rare accretion ignition-shut-down events - changing-look AGN - as they are transitioning. To track how the X-ray corona comma UV-optical accretion disk comma and optical broad-line region respond to a sudden comma major change in accretion rate comma we propose joint ToO observations of XMM-Newton openParEPIC+OMclosePar and VLT openParFORS2closePar to obtain at least two observations per triggered object openParmaximum of 4 ignition events and 4 shutdown eventsclosePar. We will constrain the extent of these drastic flux changes and yield crucial constraints on how the different structural AGN components respond to dramatic changes of the accretion rate.