If you want to appreciate or depreciate an item or a specific item ledger entry, you must use the revaluation journal.
First, you must fill in the revaluation journal with information about the current, calculated value of the specified item. You can do this manually or use the Calculate Inventory Value batch job.
If you entered a line manually, the journal will revalue all units that are linked to this item ledger entry, regardless of their posting date.
Open the 
Revaluation
Journal window.
In the Item No. field, click
the AssistButton 
. The Item List window appears.
Select the item that you want to revalue and click OK.
In the Applies-to Entry field, click the
AssistButton . The Item Ledger Entries window appears, showing
all item ledger entries relating to this item.
Select the specific item ledger entry that you want to revalue and click OK.
Repeat the procedure for each item that you want to revalue.
You can now revalue the selected item ledger entries.
Filling in the Revaluation Journal