Take Node between Two Nodes

I have Xml In the below Format

<?xml version="1.0" encoding="UTF-8"?>
<htmlString>
<ACTION v="Search"/>
<KEY/>
<ACCOUNTNO v=""/>
<AGREEMENTREF1/>
<AGREEMENTREF2/>
<PAYMENTREF1/>
<PAYMENTREF2/>
<PROGRAM v="SOW03301"/>
<SESSION v="SF3gGV1J4501"/>
<OBJECT v="1"/>
<HTMLFILE v="CGIOTP000023/TEMP:WHTTP"/>
<PIPECOUNTER v="100000386"/>
</htmlString>

I need the Part between ACTION and SESSION as a string.

<KEY/>
<ACCOUNTNO v=""/>
<AGREEMENTREF1/>
<AGREEMENTREF2/>
<PAYMENTREF1/>
<PAYMENTREF2/>
<PROGRAM v="SOW03301"/>

Can you help on this.Thanks in advance.