I have a LOT tracking system and the LOT numbers can not be duplicated.  YYMMDD## I want to duplicate the record and sub forms but change the ## before doing  it so the record won't be a duplicate.  I've tried from a report to check the box and click on the duplicate icon only to have it fail.  Any way I can do this via a program or catch it before it it tries to store the record?

Thanks

Andy