Manager Attribute

Looking at the OpenLDAP schema it appears to use the "manager" attribute the filed requires the dn: of the object. Is there another attribute similar to the manager attribute that will take a simple syntax such as "John Doe". There are a good deal of managers in our organization that don't have LDAP accounts and therefore naturally don't have a DN to specify in this field. I don't want the extra overhead of creating these DN's just for the sake of using this this attribute if I don't have to.

Thanks.