The first thing is that there is an instance to be replaced, so add an instance to an art board and then select that instance or instances, you can select multiple instances of that design. You can also replace multiple instances of different designs so if you have a square instance and a circular instance then they can be changed in seconds with a single design.
With the instances selected, go to the panel and select a different preset and then go to the right side menu and select the replace command
Add multiple instances and then select them all and go to the panel and select a particular preset and then right side menu and use the menu command. After you apply the command, all the designs selected are changed into the new one.
If you apply the artwork using the sprayer tool and create multiple instance, and then go to the size / stainer etc and modify those instances such as increasing or decreasing or rotating the artwork, once you apply the command (right side menu of the panel) to change the instance to the new selected item then all the sizes and rotations are reflected in the update. So if you have small designs then all the new instances will also be small or vica versa.
You can select an instance on the art board using the selection tool and then go to the middle of the art board and change the preset to a new one. It does mean that you don't have to apply any command etc. Simply click the entry and the item on the art board will change. If you have other similar designs, they are not changed. If you have them all selected and click the entry then they will all update. Weirdly, if you apply the sprayer tool and have instances applied then the option is not available which makes little sense as that would be a useful place to have the feature, however it can be done via the menu command.
The menu command works in exactly the same way as before but any color additions added to the dynamic instances are ignored and lost and the symbol generated is as in the panel. If you want to re-color the dynamic preset then you will need to select the direct selection tool and re-color the new design