<?xml version="1.0" encoding="utf-8" ?>
<MyFriends>
  <Man>
    <name>Ваня</name>
    <surName>Иванов</surName>
    <dateOfBirth> 09 . 05 . 1922 </dateOfBirth>
    <category>друг</category>
    <phone> 778899 </phone>
    <mobilePhone> 0455789870 </mobilePhone>
    <location>Россия, Башкортостан, Пр.Гагарина д. 63 , кв. 59 </location>
  </Man>
  <Man>
...

ArrayList ar = new ArrayList();
            string path = @"FileName.xml";

            XPathDocument xpdoc = new XPathDocument(path);
            
            XPathNavigator nav = xpdoc.CreateNavigator();
            XPathNodeIterator iterator = nav.Select("MyFriends/Man[name='Ваня' and surName='Иванов']");
            
            iterator.MoveNext();
            
            ar.Add(iterator.Current.Value);

ArrayList ar = new ArrayList();
            string path = @"..\..\MyFriends.xml";
            //Так мы можем вытянуть информацию о искомой записи по элементно
            XmlDocument doc = new XmlDocument(); doc.Load(path); XmlNode root = doc.DocumentElement;
            XmlNode node = root.SelectSingleNode("Man[name=Ваняand surName='Иванов']");
            XmlNodeList list = node.ChildNodes;
            for (int i =  0 ; i < list.Count; i++)
                ar.Add(list.Item(i).InnerText);

XmlDocument doc = new XmlDocument(); doc.Load(path); XmlNode root = doc.DocumentElement;
            XmlNode node = root.SelectSingleNode(String.Format("Man[name='{0}' and surName='{1}']", name, surName));
node.RemoveAll();
            doc.Save(path);

<Man></Man>

XmlDocument doc = new XmlDocument(); doc.Load(path); XmlNode root = doc.DocumentElement;
            XmlNode node = root.SelectSingleNode(String.Format("Man[name='{0}' and surName='{1}']", name, surname));
            XmlNode outer = node.ParentNode;
            outer.RemoveChild(node);
            doc.Save(path);