One of my requirements is to let the users know which fields they are required to fill before they can take an action. The users can take one of three actions save, submit or approve and the required fields are different based on each action. Save requires the least number of fields, submit requires the fields required for save and additional fields and approve requires all the required fields. Users can save once but submit multiple times with revisions.
What is the best way to display required field indicators based on actions that change the set of required fields?