Reversing a Usage Decision / Valuation

Hello a Usage Decision was made in QA32 but the Quantity posted in the Inspection Lot stock was incorrect. Is there a way to change the Valuation code from Accepted back to Not Valuated so that the correct quality posted quantity can be changed to the correct poundage and then the lot can be UD correctly? Please let me know.

Thank you for your help in advance.

Dragos