Modify values in xml

Modify values in xml

I have a xml file in following format :
<?xml version="1.0" encoding="utf-8"?>
<appSettings>
<property name="EXTERNAL_FILESERVER"
value="/site/bugbase.adobe.com/files/" />
<property name="FTP_USER" value="password" />
<property name="FTP_SERVER" value="sjshare.corp.adobe.com"/>
<property name="FTP_PASSWORD" value="password" />
<property name="FTP_READ_USER" value="password" />
<property name="FTP_READ_PASS" value="password" />
<property name="WORKFLOW_NOTIFICATION_TEMPLATE"
value="util/workflow_notification_template.html"/>
</appSettings>
I wanted to change password values for all the users.
Code i tried so far :
XmlDocument doc = new XmlDocument();
string path = @"C:\Users\karansha\Desktop\config file 1.xml";
doc.Load(path);
doc.SelectNodes("/appSettings/property").Item(1).Attributes["value"].Value
= "password1";
doc.SelectNodes("/appSettings/property").Item(2).Attributes["value"].Value
= "password2";
doc.SelectNodes("/appSettings/property").Item(3).Attributes["value"].Value
= "password3";
doc.SelectNodes("/appSettings/property").Item(4).Attributes["value"].Value
= "password4";
doc.Save(path);