If you want to appreciate or depreciate an item or a specific item ledger entry, you must use the revaluation journal.
To revalue inventory
Select Search (Alt+Q) 
in the upper-right corner, enter Revaluation Journal, and then choose the related link.
Choose the Calculate Inventory Value action.
On the Calculate Inventory Value page, fill in the fields as necessary. Hover over a field to read a short description.
Choose the OK button.
On each line on the Item Revaluation Journals page, in the Unit Cost (Revalued) field, enter the new unit cost. Alternatively, enter the new total amount in the Inventory Value (Revalued) field.
The relevant fields are automatically updated. The Amount field shows the actual change in inventory value for the selected item ledger entry. It calculates the difference between the Inventory Value (Calculated) field and the Inventory Value (Revalued) field.
When you have completed all lines in the revaluation journal, choose the Post action.
New value entries are now created to reflect the revaluations that you have posted. You can see the new values on the respective item cards.
Related information
Design Details: Revaluation
Inventory
Sales
Purchasing
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