Approval when a field is changed by a user

I have a field in a form called 'contact'. When a user changes that field, I would like it to be approved first either by admin or another user who may be a manager.

What I need are simple workflows which starts with a form, then alerts via email the next person that can approve or decline, then to another, then to an alert via email for requests that has gotten approval from both and viewable in a report.