https://bugs.openldap.org/show_bug.cgi?id=7462
--- Comment #6 from Quanah Gibson-Mount quanah@openldap.org --- (In reply to Quanah Gibson-Mount from comment #5)
Actually code prevents deletes so slapmodify while slapd is offline is the solution.
never mind, you can delete the entire overlay config, and then recreate, which would be the online way to handle this.