How to edit fields in line items?

Hi,
I'm creating a commerce school site, where administrator can add studies to the cart.
When he adds a product (drum lesson) i need to collect informations :
-name of the student
-level
-...

So I start to custom a line item with fields, then i try option with attribute module but i'm going in cercle..
The administrator can reorder a order (reorder module), because each year the student study drum but the level change!
So when I reorder, I need to modify the study field (term reference), but how can I modify fields in an order, or in the cart?
I can't in the order page, the only page which is not configurable!! Why this page do not take in consideration line items fields created ??
Regards,