Maha Sila Viravongs states that this ritual does not concern lay people.  Later, Lao people adopted some Brahman rituals and included them into this ritual.  In Brahmanism, the people would make floats and lanterns to worship Brahma, Vissanu, and Siva from the full moon night of the twelfth lunar month until the first waxing moon of the first lunar month.  After that they would float all the floats and lanterns in the river for cleansing off their sins and misfortunes.  Later, Lao people adopted all activities, changing the original purpose of the ritual to the worshipping of the Buddha and to thank the river goddess for providing water for human consumption.  In Thailand, people include one more activity in this ritual; Devo Rohana offering food to monks, and listening to the Devo Rohana sermon.