code: public function refreshFields()
      {
          if ($this->id === null) {
              $this->original = [];
              return $this->fields = [];
          }
  
          $sectionsBackup = isset($this->fields['IBLOCK_SECTION']) ? $this->fields['IBLOCK_SECTION'] : null;
  
          $this->fields = static::query()->getById($this->id)->fields;
  
          if (!empty($sectionsBackup)) {
              $this->fields['IBLOCK_SECTION'] = $sectionsBackup;
          }
  
          $this->fieldsAreFetched = true;
  
          $this->original = $this->fields;
  
          return $this->fields;
      }
docs: Refresh element's fields and save them to a class field.
  
  @return array