Hello @00000 ! Thank you for writing in the forum.
From what I can understand, you are trying to set a value to a property, and that value should be the time when a property changes.
This could be accomplished with the following steps:
1. Create a workflow that triggers when the property in question changes.
2. Create a new custom “date and time” property that will hold the date and time the property changed (see screenshot 1).
3. Add a step (set property value) to the workflow that sets a property value. When the property is a datetime property, like the one you created previously, it enables you to add the date and time of the step (see screenshot 2).
4. After the w/f runs you will get the datetime of the step (see screenshot 3).
Screenshot 1.
Screenshot 2.
Screenshot 3.
Should you need further assistance with this don’t hesitate to ask.
Hope my answer helped you with your usecase, if so, please mark this answer as accepted 