From AnthroWiki

Incorporation (from Latinincorporatio „to enter into a body”) is the partial and often only temporary occupation of an already existing body by a spiritual being. It differs from incarnation, in which the soul already moves into the body at conception and completely permeates it, i.e. all the members of the being. In the case of mere incorporation, on the other hand, not all members are completely permeated by the spiritual being.

A special exceptional case is the complete incarnation of the Christ in the already existing body of Jesus, which began with the Jordan baptism.