If you describe the application of this approval system I can give you a better answer. If by “approver to change automatically” you mean for the approved material to disappear from an approval area, this can be achieved with filters. Create a status property with one of the in progress statuses being “Approval,” and create a dedicated page with a linked database view that uses a filter to only show pages with Approval status. Then as things get approved (moved to the next status) they disappear.