Exorcism was the employment of one spirit to control or banish another, and these tactics were also utilized for frightening ghosts and spirits. 
The evolution of religious observances progressed from placation, avoidance, exorcism, coercion, conciliation, and propitiation to sacrifice, atonement, and redemption. 
Propitiation was insurance against immediate ill luck rather than investment in future bliss. And the rituals of avoidance, exorcism, coercion, and propitiation all merge into one another. 
See also: UB 87:6.