This workflow action clears the selected model's property or a model's property on any model related to the source model. If the related model is one-to-many, this will clear the property on all instances that apply. For example, an employee might go on long-term leave, and a new person joins your company to replace them temporarily. You can have a Replaced by property in the model that you populate with the new employee name, and when the original employee returns, you can clear this property.