How to reverse lean mfg transactions to correct cardex

Hi Team

I am not very familiar with orderless or lean mfg module

User has managed to complete a lean item which did not have costs in system

This led to the cardex not getting updated as well as the F41021

Accounting followed AFTER costs were entered into the system and so the GL F0911 shows correct quantities and costs etc

User wants me to SQL the data into F4111/F41021 but I am not wanting to use this approach for obvious reasons - F4111 is massive and should be handled with care

Question is, HOW can we reverse everything from point of F0911 knowing that the LCs had no costs on completion?