In OM (R12) where would I go to disallow requestors from cancelling or decreasing lines on their int

 Hey,

Our warehouse wants to disallow requestors from decreasing or cancelling quantities on their requisitions once the warehouse has pick released the corresponding internal sales order.  They pick release their orders several days out, so they don't want the requestors to be able to make any changes as they aren't aware of it until they go to ship confirm.

Pernille