AFAIK, you might only “rectify” the situation through debug — service the job, alter the value(s) in memory and continue. That assumes the job is stopped at an instruction and waiting on a response. And that the programming can be successfully debugged.
Keep in mind that if one record has a decimal data error, then other records can easily have the same kind of problem. You might need to correct any number of them before the job finishes. Also be careful which values you change in memory — that you change the right ones and that you appropriately change all related ones.
IMO, your better choice is to let the job fail, correct all decimal data errors and run a recovery. Then run the job again.