It can be integration or disintegration, yes, but I did'nt say that you can't move to an otther type. It's just that it is not really a "move" in the typical sense. It's just that we can experience the passion others types. For example, even if you are a 8, you can experiment depression because of the loss of a source of love, like 4s do, or to experiment fear because you envisage a worst case scenario, like 6s do. Enneagram is a map of the human condition, and the passions and mental fixations of each type form differents pieces of that map. That mean that as a human being, you can experiment the passions or mental fixations of another type than the your. Actully, you can experiment every.
But hte thing is that their is one idea, impression, way to solve information that you spontaneously use, especially when yu are entranced. 4s, for example don't just experiment depression, they feel loss of love as the fundamental basis of their life, and the impression that a source of love has been lost and denied because of semthing wrong and lacking in their image is the truth, 6s on the other hand, don't just envisasge worst case scenario and are afraid, they consider negative past experiences, paranoia and doubt as the legitime source of information and hardly consider the best. This is I think the trifix is confusing, wirtually impossible to find and based on subjectives impressions.