Change price of Vendor Consignment after MRKO

Dear SAP Experts,

I've facing a problem regarding change price of vendor consignment after Consignment Settlement (MRKO).

What I'd like to do is posting Additional Credit Memo/ Debit Memo (MIRO), or Revaluation(MRNB) for changed price (ME12) after Consignment Settlement .

However, I found out those functions are acceptable only for GR-based. Because of consumed base, vendor consignment cannot be executed.

(Client mainly buy chemical material via consignment, and vendor tell them that those material changed price next month. Thus this requirement has to be applied in SAP)

Does anyone can help me, please.