Hello,
GRN qty change is possible after taking UD reversal but still there is no option to change SPECIFICATIONS AND THERE RESULTS.
Bcoz when you process RR table entries updated and there is no way of change the lot results and specs.
there is only one way to cancel the lot and reassign the plan and regenerate the inspection lot after GRN.
Or other wise table level update in SAP which is not recommended.
Regards