diff --git a/admin/admin-cli.php b/admin/admin-cli.php
index 69f6e22f53..dcd7a06758 100755
--- a/admin/admin-cli.php
+++ b/admin/admin-cli.php
@@ -27,12 +27,13 @@ else
 {
 	$action = '--help';
 }
-
 // this is kind of a hack, as the autocreate_session_callback can not change the type of the loaded account-class
 // so we need to make sure the right one is loaded by setting the domain before the header gets included.
 $arg0s = explode(',',@$arguments[0]);
 @list(,$_GET['domain']) = explode('@',$arg0s[0]);
 
+if (is_dir('/tmp')) ini_set('session.save_path','/tmp');	// regular users may have no rights to apache's session dir
+
 $GLOBALS['egw_info'] = array(
 	'flags' => array(
 		'currentapp' => 'admin',
@@ -47,6 +48,9 @@ switch($action)
 {
 	case '--delete-user':
 		return do_delete_user($arg0s[2],$arg0s[3]);
+		
+	case '--change-account-id':
+		return do_change_account_id($arg0s);
 
 	default:
 		usage($action);
@@ -94,6 +98,8 @@ function usage($action=null,$ret=0)
 	
 	echo "--delete-user admin-account[@domain],admin-password,account-to-delete[,account-to-move-data]\n";
 	echo "	Deletes a user from eGroupWare. It's data can be moved to an other user or it get deleted too.\n";
+	echo "--change-account-id admin-account[@domain],admin-password,from1,to1[...,fromN,toN]\n";
+	echo "	Changes one or more account_id's in the database (make a backup before!).\n";
 	exit;	
 }
 
@@ -139,3 +145,246 @@ function do_delete_user($user,$new_user=0)
 	echo "Account '$user' deleted.\n";
 	return 0;
 }
+
+
+function do_change_account_id($args)
+{
+	/**
+	 * App-, Table- and column-names containing nummeric account-id's
+	 * @var array
+	 */
+	$columns2change = array(
+		'phpgwapi' => array(
+			'egw_access_log'     => 'account_id',
+			'egw_accounts'       => array(array('account_id','.type'=>'abs'),'account_primary_group'),
+			'egw_acl'            => array('acl_account','acl_location'),
+			'egw_addressbook'    => array('contact_owner','contact_creator','contact_modifier','account_id'),
+			'egw_addressbook2list' => array('list_added_by'),
+			'egw_addressbook_extra' => 'contact_owner',
+			'egw_addressbook_lists' => array('list_owner','list_creator'),
+			'egw_api_content_history' => 'sync_changedby',
+			'egw_applications'   => false,
+			'egw_app_sessions'   => 'loginid',
+			'egw_async'          => 'async_account_id',
+			'egw_categories'     => 'cat_owner',
+			'egw_config'         => false,
+			'egw_history_log'    => 'history_owner',
+			'egw_hooks'          => false,
+			'egw_interserv'      => false,
+			'egw_lang'           => false,
+			'egw_languages'      => false,
+			'egw_links'          => 'link_owner',
+			'egw_log'            => 'log_user',
+			'egw_log_msg'        => false,
+			'egw_nextid'         => false,
+			'egw_preferences'    => array(array('preference_owner','preference_owner > 0')),
+			'egw_sessions'       => false,	// only account_lid stored
+			'egw_vfs'            => array('vfs_owner_id','vfs_createdby_id','vfs_modifiedby_id'),	// 'vfs_directory' contains account_lid for /home/account 
+		),
+		'etemplate' => array(
+			'egw_etemplate'      => 'et_group',
+		),
+		'bookmarks' => array(
+			'egw_bookmarks'      => 'bm_owner',
+		),
+		'calendar' => array(
+			'egw_cal'            => array('cal_owner','cal_modifier'),
+			'egw_cal_dates'      => false,
+			'egw_cal_extra'      => false,
+			'egw_cal_holidays'   => false,
+			'egw_cal_repeats'    => false,
+			'egw_cal_user'       => array(array('cal_user_id','cal_user_type' => 'u')),	// cal_user_id for cal_user_type='u'
+		),
+		'emailadmin' => array(
+			'egw_emailadmin'     => false,
+		),
+		'felamimail' => array(
+			'egw_felamimail_accounts'      => 'fm_owner',
+			'egw_felamimail_cache'         => 'fmail_accountid',	// afaik not used in 1.4+
+			'egw_felamimail_displayfilter' => 'fmail_filter_accountid',
+			'egw_felamimail_folderstatus'  => 'fmail_accountid',	// afaik not used in 1.4+
+			'egw_felamimail_signatures'    => 'fm_accountid',
+		),
+		'infolog' => array(
+			'egw_infolog'        => array('info_owner',array('info_responsible','.type' => 'comma-sep'),'info_modifier'),
+			'egw_infolog_extra'  => false,
+		),
+		'news_admin' => array(
+			'egw_news'           => 'news_submittedby',
+			'egw_news_export'    => false,
+		),
+		'projectmanager' => array(
+			'egw_pm_constraints' => false,
+			'egw_pm_elements'    => array('pe_modifier',array('pe_resources','.type' => 'comma-sep')),
+			'egw_pm_extra'       => false,
+			'egw_pm_members'     => 'member_uid',
+			'egw_pm_milestones'  => false,
+			'egw_pm_pricelist'   => false,
+			'egw_pm_prices'      => 'pl_modifier',
+			'egw_pm_projects'    => array('pm_creator','pm_modifier'),
+			'egw_pm_roles'       => false,
+		),
+		'registration' => array(
+			'egw_reg_accounts'   => false,
+			'egw_reg_fields'     => false,
+		),
+		'resources' => array(
+			'egw_resources'      => false,
+			'egw_resources_extra'=> 'extra_owner',
+		),
+		'sitemgr' => array(
+			'egw_sitemgr_active_modules'   => false,
+			'egw_sitemgr_blocks'           => false,
+			'egw_sitemgr_blocks_lang'      => false,
+			'egw_sitemgr_categories_lang'  => false,
+			'egw_sitemgr_categories_state' => false,
+			'egw_sitemgr_content'          => false,
+			'egw_sitemgr_content_lang'     => false,
+			'egw_sitemgr_modules'          => false,
+			'egw_sitemgr_notifications'    => false,
+			'egw_sitemgr_notify_messages'  => false,
+			'egw_sitemgr_pages'            => false,
+			'egw_sitemgr_pages_lang'       => false,
+			'egw_sitemgr_properties'       => false,
+			'egw_sitemgr_sites'            => false,
+		),
+		'syncml' => array(
+			'egw_contentmap'        => false,
+			'egw_syncmldeviceowner' => false,	// Lars: is owner_devid a account_id???
+			'egw_syncmldevinfo'     => false,
+			'egw_syncmlsummary'     => false,
+		),
+		'timesheet' => array(
+			'egw_timesheet'      => array('ts_owner','ts_modifier'),
+			'egw_timesheet_extra'=> false,
+		),
+		'wiki' => array(
+			'egw_wiki_interwiki' => false,
+			'egw_wiki_links'     => false,
+			'egw_wiki_pages'     => array(array('wiki_readable','wiki_readable < 0'),array('wiki_writable','wiki_writable < 0')),	// only groups
+			'egw_wiki_rate'      => false,
+			'egw_wiki_remote_pages' => false,
+			'egw_wiki_sisterwiki'=> false,
+		),
+		'phpbrain' => array(	// aka knowledgebase
+			'phpgw_kb_articles'  => array('user_id','modified_user_id'),
+			'phpgw_kb_comment'   => 'user_id',
+			'phpgw_kb_files'     => false,
+			'phpgw_kb_questions' => 'user_id',
+			'phpgw_kb_ratings'   => 'user_id',
+			'phpgw_kb_related_art' => false,
+			'phpgw_kb_search'    => false,
+			'phpgw_kb_urls'      => false,
+		),
+		'polls' => array(
+			'phpgw_polls_data'   => false,
+			'phpgw_polls_desc'   => false,
+			'phpgw_polls_settings' => false,
+			'phpgw_polls_user'   => 'user_id',
+		),
+		// MyDMS	ToDo!!!
+		// VFS2		ToDo!!!
+	);
+	
+	$ids2change = array();
+	for($n = 2; $n < count($args); $n += 2)
+	{
+		$from = (int)$args[$n];
+		$to   = (int)$args[$n+1];
+		if (!$from || !$to) die("\nAccount-id's have to be integers!\n\n");
+		$ids2change[$from] = $to;
+	}
+	$total = 0;
+	foreach($columns2change as $app => $data)
+	{
+		$db = clone($GLOBALS['egw']->db);
+		$db->set_app($app);
+		
+		foreach($data as $table => $columns)
+		{
+			if (!$columns)
+			{
+				echo "$app: $table no columns with account-id's\n";
+				continue;	// noting to do for this table
+			}
+			if (!is_array($columns)) $columns = array($columns);
+			
+			foreach($columns as $column)
+			{
+				$type = $where = null;
+				if (is_array($column))
+				{
+					$type = $column['.type'];
+					unset($column['.type']);
+					$where = $column;
+					$column = array_shift($where);
+				}
+				$total += ($changed = _update_account_id($ids2change,$db,$table,$column,$where,$type));
+				echo "$app: $table.$column $changed id's changed\n";
+			}
+		}
+	}
+	echo "\nTotal of $total id's changed.\n\n";
+}
+
+function _update_account_id($ids2change,$db,$table,$column,$where=null,$type=null)
+{
+	static $update_sql;
+	
+	if (is_null($update_sql))
+	{
+		foreach($ids2change as $from => $to)
+		{
+			$update_sql .= "WHEN $from THEN $to ";
+		}
+		$update_sql .= "END";
+	}
+	switch($type)
+	{
+		case 'comma-sep':
+			if (!$where) $where = array();
+			$where[] = "$column IS NOT NULL";
+			$where[] = "$column != ''";
+			$db->select($table,'DISTINCT '.$column,$where,__LINE__,__FILE__);
+			$change = array();
+			while(($row = $db->row(true)))
+			{
+				$ids = explode(',',$old_ids=$row[$column]);
+				foreach($ids as $key => $id)
+				{
+					if (isset($account_id2change[$id])) $ids[$key] = $account_id2change[$id];
+				}
+				$ids = implode(',',$ids);
+				if ($ids != $old_ids)
+				{
+					$change[$old_ids] = $ids;
+				}
+			}
+			$changed = 0;
+			foreach($change as $from => $to)
+			{
+				$db->update($table,array($column=>$to),$where+array($column=>$from),__LINE__,__FILE__);
+				$changed += $db->affected_rows();
+			}
+			break;
+			
+		case 'abs':
+			if (!$where) $where = array();
+			$where[$column] = array();
+			foreach(array_keys($ids2change) as $id)
+			{
+				$where[$column][] = abs($id);
+			}
+			$db->update($table,$column.'= CASE '.$column.' '.preg_replace('/-([0-9]+)/','\1',$update_sql),$where,__LINE__,__FILE__);
+			$changed = $db->affected_rows();
+			break;
+			
+		default:
+			if (!$where) $where = array();
+			$where[$column] = array_keys($ids2change);
+			$db->update($table,$column.'= CASE '.$column.' '.$update_sql,$where,__LINE__,__FILE__);
+			$changed = $db->affected_rows();
+			break;
+	}
+	return $changed;
+}