Formative Assessment and Parents

My administrator has included me in a district wide research assessment group. The goal of our group is to deconstruct standards into student friendly language and teach formatively with a process that directly ties into the standards. I love the training and can clearly see a great value to this, BUT I am unsure how to deal with parents.

If I were to implement this in my classroom, there would still be assignments that are "graded" but not for a grade merely for feedback. The only grades would be the tests. How do you deal with the parents that are so used to seeing grades? I especially find this the hardest with my advanced placement classes.