I found solution.
This will get dept_id on open new ticket so client will only need to put subject and body.
Department:
-Vaša firma-
<?
$deptIdUser = $thisclient->getDeptId();
$services= db_query('SELECT dept_id,dept_name FROM '.DEPT_TABLE.' ORDER BY dept_name');
while (list($deptId,$dept) = db_fetch_row($services)){
//$selected = ($info==$deptId)?'selected':'';
$selected = ($deptIdUser==$deptId)?'selected':''; ?>
"<?=$selected?>><?=$dept?>
<?
}?>
* <?=$errors?>