Hi Stuart!
I tried like you adviced but I have got a problem. 
I modified schema, deleted data and insert new data, so now my data in Tamino is like the following:
----------------------------------
Atkins
Paul
Male
1964
Harbour Close
23
Portsmouth
PO2056HAR
GreenStreet
10
Berlin
AB900B
Professional Diver
…
----------------------------------
After executing sample script php, I got in Tamino the following data:
----------------------------------
Atkins
Paul
Male
1964
Harbour Close
23
Portsmouth
PO2056HAR
Kwiatowa
5
Warsaw
00-950
GreenStreet
10
Berlin
AB900B
Kwiatowa
5
Warsaw
00-950
Professional Diver
…
----------------------------------
So the php script added two nodes, and now I have got four addresses. 
How should I modify this php script?
In advance, thanks a lot!
best regards,
Dariusz Baumann
PS.
Here is php script:
----------------------------------
<?php
header("Content-Type: text/html; charset=UTF-8");
include "TaminoAPI.php";
include "TaminoHelperFunctions.php";
$PC_HOST = "localhost";
$PC_PORT = "80";
$PC_DATABASE = "mydb";
$PC_COLLECTION = "Hospital";
$PC_DOCTYPE = "patient";
$PC_ENCODING = "UTF-8";
$PC_USERNAME = "";
$PC_PASSWORD = "";
$tamino = &new TaminoAPI($PC_HOST,
$PC_PORT,
$PC_DATABASE,
$PC_USERNAME,
$PC_PASSWORD);
$tamino->setCollection($PC_COLLECTION);
$tamino->setEncoding($PC_ENCODING);
$surname = "Atkins";
$xquery = "update for \$a in input()/$PC_DOCTYPE ".
"where \$a/name/surname = \"$surname\" ".
"do insert ".
" ".
"Kwiatowa ".
"5 ".
"Warsaw ".
"00-950 ".
" ".
"following \$a/address ";
if (!($tamino->xquery($xquery)))
{
echo "ERROR
";
thfPrintError($tamino);
}
else
{
echo "OK.
";
}
?>
----------------------------------
#webMethods#API-Management#Tamino