Goddess Kali is worshiped on the day in temples and special pujas and rituals are held on the day.
Sri Ramakrishna Paramahamsa performed special rituals on the day. He used to invoke Mother Goddess on the day.
It must be also noted here that Phalaharini is a form of Goddess Kali in the Tantric school of teaching. This form of Kali is propitiated for destroying the results of actions - all Karma Phala are removed through her worship. Thus no sins due to actions on earth. She is the destroyer of the effects of bad karma.
Importance Of Phalaharini Kali Puja
All of us are here in this world because each one of our actions produces an impression on our minds and that impression propels us to do more actions. If I do a good action it leaves a good impression on my mind, which is called samskara — it is also called karma or karma-phala and that would make me do another good action and this goes on and on till I understand that I am not the doer. Till I have the sense of doership this samskara or karma-phala is generated. Kali is called — particularly in the context of Phalaharini Kali puja — Phalaharini, because she has the power to destroy all the karmas or samskaras of our lives. She has the power to give you and I liberation from the cycle of repeated births and deaths, repeated coming and going. So it is quite significant that Sri Ramakrishna surrendered all the fruits of his spiritual austerities on the Phalaharini Kali puja day, at the feet of his wife.
Ratanti Kali Puja in Magh month