Umbraco v6 change document type of a node

UmbracoChangeDocType

@using Umbraco.Core.Models;
@using Umbraco.Core.Services;

var contentService = ApplicationContext.Current.Services.ContentService;
var contentTypeService = ApplicationContext.Current.Services.ContentTypeService;
var contentType = contentTypeService.GetContentType(4200);

var content = contentService.GetById(2052);
content.ChangeContentType(contentType);
contentService.Save(content);