If you have lot of instances of an object which not a prefab, you can replace all instances with a prefab.

How to use: -Put "PrefabCorrectorInspector.cs" to Assets/Editor directory. -Create ean empty game object and assign "PrefabCorrector.cs" script to it. -Make prefab one of the instances. -Select all instances and add them to "Object List" array on the inspector. -Put the prefab to the "Prefab" on the inspector. -Click correct and done!