If you need to change the direct unit cost for several items, you can use the Adjust Item Costs/Prices batch job.
The batch job changes the contents of one of the fields on the item card that determines the unit price. The contents of the field are changed in the same way for all items or selected items. The batch job does this by multiplying the value in the field by an adjustment factor that you specify.
Open the 
Adjust
Item Costs/Prices batch job request form.
On the Item tab, you can set filters to select the items processed in the batch job.
On the Options tab, specify the other conditions for the batch job. For Help about a specific field, click the field and press F1.
Click OK to start the batch job.