Scheduling and Engineering woes

To all,
Our production department is scheduling (but not releasing) jobs
several months out. The problem is that occasionally, the BOM or
routing may change from the time the job is created and scheduled to
the time it is eventually released.

Right now if something changes on the BOM or routing, engineering is
tasked with checking Time Phase to see if the change will affect an
upcoming job.

What is the best way to handle this? Should scheduling just delete
the job before releasing it and create a new one with the new methods
of mfg? Or is there an easier way to pull in the new methods to an
existing job?

Thanks in advance!