WSO2: How to replace a string in the request body - replace

Question

We have a very simple EI API. We receive an XML payload, we then extract a destination code from the XML document and, based on the destination code, we forward the payload to the appropriate endpoint.
One of our clients have made a spelling mistake in their payload and we want to correct it before we send it to the new endpoint. We want to replace the word 'Principle' with 'Principal'.
How can we replace a string in the request body with another string?
Here is our current implementation:
<inSequence>
<property expression="//MyXML/Destination" name="Destination" scope="default" type="STRING"/>
<log level="custom">
<property expression="//MyXML/Transaction/Destination" name="Destination"/>
</log>
<property action="remove" name="REST_URL_POSTFIX" scope="axis2"/>
<property description="vendorId" expression="concat('gov:/integration/endpoints/myendpoints/', get-property('uri.var.vendorId'), '_EP')" name="vendorId" scope="default" type="STRING"/>
<log category="DEBUG" description="request_log" level="full">
<property expression="get-property('vendorId')" name="Vendor ID"/>
</log>
<log description="request_log" level="custom">
<property expression="get-property('vendorId')" name="Vendor ID"/>
</log>
<send>
<endpoint key-expression="get-property('vendorId')"/>
</send>
</inSequence>