Order defined by the sortorder, this can be any attribute and if left out it is the database order, which is mostly when it is generated, but that is not sure.
If your datasource is from database (Database/XPath) use a specific integer attribute: SortOrder and swap the sortorder values. Sorter order should be the order in the grid.
If you use NP objects the list is ordered by creating or you sort it in a microflow (Datasource microflow)
In that case do the swap in the microflow. That can be though, so a SortOrder attribute is also helpful here.