Can two wives agree to swap rota days because of a particular need?

Yes, as long as the swap of rota days is made willingly and with the agreement of the wife concerned, not under pressure. Sometimes a wife needs to swap days because of certain matters, and the husband can allow it if the other wife agrees gladly. Make sure there is no subtle pressure or sense of being forced, because consent that is not sincere is not justice. Record the swap so it is not forgotten and no misunderstanding arises later. Make swaps an occasional convenience, not a way for the husband to favour one wife permanently. If swaps become a source of dispute, refer to the religious office. See rotation.