lib/Tumblr/API/Client.php
public function unlike($postId, $reblogKey)
    {
        $options = array('id' => $postId, 'reblog_key' => $reblogKey);

        return $this->postRequest('v2/user/unlike', $options, false);
    }
public function unlike($postId, $reblogKey)
    {
        $options = array('id' => $postId, 'reblog_key' => $reblogKey);

        return $this->postRequest('v2/user/unlike', $options, false);
    }
Unlike a post

@param int    $postId    the id of the post
@param string $reblogKey the reblog_key of the post

@return array the response array