Edit List Item actions are similar to Modify List Item actions, except they are executed against a single item and the action form presented to the user displays the current values of the columns that can be edited by the user.
It works in a similar manner to the Edit Item option on the Basic Grid’s or Basic Calendar’s Context Menu, except the action form shows only the columns identified in the action, rather than all columns in the associated list or library. If the user attempts to execute this action against multiple items at once, it will only allow the user to edit the first item in the first list located by the Data Display.