If Shraddham falls on Dwadashi day, one must only prepare the Shraddha feast (thaligai). In some households, they prepare only the food items meant for Dwadashi Parana. They offer the same to the Bhoktas (priests/guests). After that, with the Bhokta’s permission, the Kartha (performer) may also consume the Parana food. In some other households, the custom is to prepare only the regular Shraddha thaligai. Please follow each household’s tradition.