When you edit any field in Mendix the changes are done only in the client (i.e. they’re only on your machine) and they get posted to the server only when the object goes through a commit/save action.
For most intents and purposes that should just work for you out of the box.
If for some reason you want to completely separate the changes from the main object you can create a new object with a reference to your main object, open that in a new page, and in your save microflow port the changes into the main object.
Hope this helps