Jobs sometimes fail to achieve a successful completion. Checkpoints enable failed jobs to be restarted from the last checkpoint before the failure. Before you restart a job try to understand what caused the failure. You may need to take remedial actions before restarting the job to prevent the failure from occurring again. For further information Restarting A Job.)
When you are ready to restart the job, re-issue the same tbuild command used to submit the job the first time. The job will restart at the job step that failed, at the point in that step where the last checkpoint was taken prior to the failure.