The above example has also been proven to work in the iPlanet / Sun One Directory Server 5.0/5.1. As an example:
$attrs["mail"] = array();
ldap_mod_del($ldapConnID,$dn,$attrs);
or
$attrs["mail"] = array();
$attrs["telephonenumber"] = array();
ldap_mod_del($ldapConnID,$dn,$attrs);
This will remove all occurences of attributes in the entry specified by the dn.