ftp_cdup

<?php 
// set up basic connection 
$conn_id = ftp_connect($ftp_server); 

// login with username and password 
$login_result = ftp_login($conn_id, $ftp_user_name, $ftp_user_pass); 

// change the current directory to html 
ftp_chdir($conn_id, 'html'); 

echo ftp_pwd($conn_id); // /html 

// return to the parent directory 
if (ftp_cdup($conn_id)) { 
  echo "cdup successful\n"; 
} else { 
  echo "cdup not successful\n"; 
} 

echo ftp_pwd($conn_id); // / 

ftp_close($conn_id); 
?>