$url = 'https://creator.zoho.com/api/xml/myApplication/myForm/update/';
$fields .= '&authtoken=<authtoken>';
$fields .= '&raw=true';
$fields .= '&scope=creatorapi';
$fields .= '&reloperator=AND';
$fields .= '&criteria=field=92';
$fields .= '&Start_Date=12/27/12 14:00:00&End_Date=12/27/12 14:30:00';
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_POST, TRUE);
curl_setopt($ch, CURLOPT_POSTFIELDS, $fields);
curl_exec($ch);
curl_close($ch);