The cn=schema entry has a multivalued attribute, objectClasses, that contains definitions of each object class in the directory schema. You can delete definitions with X-ORIGIN 'user defined' by using the ldapmodify(1) command.
Because the schema is defined by the LDAP view in cn=schema, you can view and modify the schema online using the ldapsearch and ldapmodify utilities. However, you can delete only schema elements that have the value ’user defined’ for the X-ORIGIN field. The server will not delete other definitions.
Changes that you make to user-defined elements are saved in the file 99user.ldif .
View the definition of the object class to delete.
See To View an Object Class for details.
Use the ldapmodify(1) command to delete the object class definition as it appears in the schema.
The following command deletes the object class that was created in Example 11–4:
$ ldapmodify -D cn=admin,cn=Administrators,cn=config -w - Enter bind password: dn: cn=schema changetype: delete delete: objectClasses objectClasses: ( 22.214.171.124.5.6.8 NAME 'blogger' DESC 'Someone who has a blog' STRUCTURAL MAY blog X-ORIGIN 'user defined' ) ^D
Notice that you must include X-ORIGIN 'user defined', which was added by Directory Server to classify this schema definition as an extension.