Eject

You throw hands of salt onto the possessed person. You say the following words:

We know who you are [ name demon] and you shall leave.

We call upon the power of the people in the light and dark. Those who went before us and died so that we could live.

Help and mediate us.

I call forth upon the power of   [ Your names and names of people you know or knew]

After each name you trow salt over the possessed being and roll a d12 until you get to the demons hit points or over it.

Then the demon will be ejected from the host and you can now attack it without hurting the host.

Before you kill the demon you have to trow consecrated water  on the host to prevent the demon from possessing it again.