I would recommend you to make a status attribute (enumeration) in the entity of your object. then I would commit the object at the proper time (at every change of an input in your page), with the status “draft” of your enumeration.
When you save the data, I would change the status to “complete”
Drafting and saving is in Mendix creating an entity and commiting the entity.
If you just create an entity it is drafted.
At any moment you want to save it, just commit it at that moment.