title: Update cells in smartsheet
body: <p>I am trying to update some cells in an existing SmartSheet sheet with PHP. It's no problem to add new lines but I can't get the correct JSON for updating.</p>
  
  <p>My code at this moment:</p>
  
  <pre><code>$ch = curl_init("https://api.smartsheet.com/1.1/sheet/1234567890/rows/");
  
  $header = array("Authorization: Bearer xxxxxxxxxxx", 
              "Content-Type: application/json",
              "Assume-User: xxxx%40xxxx.com");
  $name = 'MyName';
  $fields =  '{"rowNumber":1, "columnId": 1234567890, "value": "'.$name.'", "displayValue": "'.$name.'"}';
  
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
  curl_setopt($ch, CURLOPT_HTTPHEADER, $header);
  curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
  curl_setopt($ch, CURLOPT_POSTFIELDS,  $fields);
  curl_setopt($ch, CURLOPT_POST, 1);
  $result = curl_exec($ch);
  </code></pre>
  
  <p>This results in:</p>
  
  <pre><code> "{"errorCode":1008,"message":"Unable to parse request. The following error occurred: Unknown attribute \"columnId\" found at line 1, column 45"}"
  </code></pre>
  
  <p>I tried many options and can't figure this out with the API documentation and can't find any other PHP examples who do the same. Does somebody know how I can update just one specific cell in a row?</p>