You can use 'Cancel changes’ action of a button to cancel any changes you made in a form, if these changes are not yet committed.
If you are looking for a way to revert an executed Microflow, there isn't a default way to do this. An executed Microflow is done and does not have a history or something to undo this Microflow. You can try to create a Microflow that works the opposite of the Microflow you want to revert.
If the object you changed is not yet committed, you can retrieve the same object from the database and compare the 2 object to look for any changes.
Hope this helps!