How do I pull individual XML values from an existing BLOB

I have a blob which I don't own and cannot change. It is a BLOB containing an XML message which I want to parse.

xml from schema browser

My parse attempt is as follows:

SELECT
   XMLTYPE( t.intfc_rqst_xml ).EXTRACT('//*/text()').getStringVal() 
FROM
   INTERFACE_MESSAGE_INFO t;

Gives this Error

ORA-06553: PLS-306: wrong number or types of arguments in call to 'XMLTYPE'

Any help appreciated!

Character set is a second parameter.

You can try the following:

...
xmltype(t.intfc_rqst_xml , nls_charset_id('AL32UTF8'))
...

Different Character Sets