How can I get a string representation of an XML::XPath object?

I have a script that is using the XML::XPath module from CPAN to manipulate an XML document by pulling in a template and setting some node text values.  The code is similar to the following:

my $notificationXML = XML::XPath->new(xml => $notificationRqst );   #where $notificationRqst is a string of XML

$notificationXML->setNodeText('/notificationRequestDtl/notificationRequestDtlHdr/priority','HIGH');


So, at this point, I have (I think) my original XML with one node value changed.  Now I want to pass the $notificationXML object to another command, which accepts a variable containing a string of XML (same as the $notificationRqst variable $notificationXML was created from.

Not sure if my question is making sense, since I'm not sure how to ask it. If you need clarification please ask.