Price change approval workflow on sales order

Business need to have approval workflow when user apply any discount on sales order.

i.e when user try to apply any discount on sales order ( hearder or lines), system send approval request to concern supervisor

Once it approved. then and then only discount get applied on sales order.

Is there any way where we can map this business requirement.

Please guide -  Basic need of this requirement is to avoid wrong discount on sales order by end user.

Amol