Besides product specification you can also use plan specification. It is mainly intended for modifying specific plan lines.
Plan specification is a specification strucure that can be created, according to requirements. Plan specification shows in lines of plan components, materials of which the item is made up as well as technological procedures used in processing.
Moreover, plan specification is product specification copied to lines of plan. Until plan specification is created it doesn't exist (blank) and product specification is used instead. Having created a plan specification the link to product specifcation is cancelled. From now on the plan specification is used.
Lines of material in plan specification contain data on materials required for creating items (products) as specified in plan.
Lines of operations of plan specification contain data on operations in the technological procedure.
Besides data from product specification you can find also lines scheduling requirements of lines of material as well as scheduling execution of operations.
Plan specification allows you to release work orders from plan.
Edit lines in plan specification in the same way as in product specification. That is, you can add new lines of material and operation, changing or deleting them later. Thus you adapt the basic product specification to concrete circumstances particular to the plan.