Umbraco change templates on multiple documents

gistfile1.cs

using System;
using System.Web;
using System.Web.Services;
using System.Collections;
using System.Web.Services.Protocols;
using umbraco.cms.businesslogic;
using umbraco.cms.businesslogic.web;
using umbraco.BusinessLogic;
using System.Xml.Serialization;
using umbraco.cms.businesslogic.property;
using umbraco.cms.businesslogic.macro;

[WebService(Namespace = "http://tempuri.org/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
public class YourWebservice : System.Web.Services.WebService
{
	[WebMethod]
	public void UpdateDocumentParent(int docId, int parentId, bool deep, int templateId)
	{
		if (deep)
		{
			ArrayList list = this.GetDocumentChildren(docId);
			for (int i = 0; i < list.Count; i++)
			{
				if (list[i] is Document)
				{
					int n;
					int.TryParse(((Document)list[i]).Id.ToString(), out n);
					if (n > 0)
					{
						try
						{
							Document d = new Document(n);
							d.Publish(new User(0));
						}
						catch { }
					}
				}
			}
		}
		else
		{
			Document d = new Document(docId);
			d.Template = templateId;
			d.Publish(new User(0));
		}
	}

	private ArrayList GetDocumentChildren(int docId)
	{
		Document doc = new Document(docId);
		Document[] children = doc.Children;
		
		ArrayList list = new ArrayList();
		if (children.Length > 0)
		{
			for (int i = 0; i < children.Length; i++)
			{
				if (children[i].HasChildren)
				{
					list.AddRange(GetDocumentChildren(children[i].Id));
				}
				list.Add(children[i]);
			}
		}
		return list;
	}
}