An approval reminder job (with job name APPR_RMNDR) is automatically created when you click the Approval Reminder Job button at the bottom of the A.20.45 Approval Templates screen.
You can change the comment as well as the time the job should run (the default time is set to 10:00 PM). This job periodically checks which users on an approval list have failed to approve and in such a that case sends an appropriate email.
The interval can be changed by the project default ZX_JOB_INT. The project default ZX_JOB_INT is used to define an interval for the DBMS job APPR_RMNDR.