invoice approval assignment/delegation with vacation rules

Summary

Standard functionality allows invoice approvals to be re-assigned or delegated to any individual in the company. How do we set up a well-controlled process?

Content

Standard functionality allows invoice approvals in Oracle to be re-assigned or delegated to any individual in the company. You of course hope that approvers will use common sense and only reassign or delegate to an individual with the same or higher level of approval authority, but hope is not a good control. In our environment, to mitigate this risk, we have disabled the option to reassign or delegate the invoice approval task. That worked fine initially because no one was going on vacation. Now however travel is picking back up and there is a legitimate need to reassign or delegate