how to Increase Price after migo

Hello gurus

My client has strange question he has GR for 10 materials and he has paid and settled and after mutual agreement after one year now management has to increase the Price of the materials, and no increase to inventory should be happen and it should load on inventory and Excise should be posted as well and credit should be taken

Any body can help this out whether this possible or not

Thanks and regards

Kaly