if you mean "Signal Edges" (Wiki: Signal Edge) or in German "Signal Flanken".
Then there is a possibility in MCD to react to those.
But I haven't done that with conditions or expression formulas (since you would have to consider the current state when evaluating the formula...).
Usually if I want to react to a signal edge (or on the change of the signal) I use operations to do that.
Because MCD operations in the sequence Editor operate in the way that they are only evaluated once when the condition is met (and not continuously when the condition remains met) it is a quite simple solution.
To do that just create a operation in the sequence editor and take the signal as condition.