Rituals
Having direct access to the physical realm and thus greater ability to collect and exert energy, an incarnated spirit's commands and will have power over the spiritual realm and all other spiritual beings. How much power depends on the incarnated spirit's sensitivity, actions, beliefs, and relationships to the spirits under their command.
Incarnated spirits who believe their actions, words, or thoughts have power over the spiritual realm have more influence than incarnated spirits who don't hold these beliefs. Incarnated spirits with high sensitivity to spiritual entities have less power over them than those with low sensitivity.
Incarnated spirits may use rituals to increase their belief in their power over the spiritual realm. Rituals performed with intent to banish spiritual activity (such as residual hauntings), to invite spirits to approach, to command spirits to act, or to revoke previous commandments can increase the potency or duration of their commands or the ability of the targeted spirits. Rituals performed repeatedly increase these effects.
Rituals, however, often attract spirits like demons, which hope to influence the incarnated spirit into using their power to forward the oppressive spirit's goals. Incarnated spirits have less control over poltergeists, demons, or other spirits attached to them.