Gather all melted wax, burned incense, copy all sigils, seals and even the chant used in the spell you want to reverse or stop. (sometimes it isn'y vailable due to throwing things in the wind or putting things in the garbage....get what you can) Gather up a grey candle. You eill need reversing oil and incense.
On a waning moon, duly cast a circle. Place the candle in the middle of the alter. Place all the items from the spell you want to reverse or stop. Using you'r athame point at the grey candle and say:
"These things I have enmagicked be will now, cease to exist, Go back the way you begun, cease now, and desist. With harm to none, and no alarm the energies dissipate, Return all things as they were, I relinguish them to fate. Nema, Nema, Nema" (make a banishing Earth pentagram and light candle) (let it burn all the way down)