A gives something (O) to someone (E). With =da, O is elevated to A: O lali+da E. With =dava, E is elevated to A: E lali+dava O. An item exchanged for can be expressed with the preposition nene. Since exchange is symmetrical, the O argument and the peripheral argument can change places.
Masedo ŋilalikeŋi haggogo leyawa?