declare
xyz clob := null;
abc clob := null;
ijk clob := null ;
v_req_xml clob := null;
 x_response_xml          XMLTYPE;
      x_soap_header_xml       XMLTYPE;
      soap_header_xml         CLOB;
      p_response_xml clob := null;
begin
select req_xml into v_req_xml from test_xml ;---I stored the response XML as a CLOB and fetching the same.
sample_procedure('v_req_xml = ',v_req_xml) ;--Sample_procedure - autonomous procedure
 x_soap_header_xml := XMLTYPE.createxml (v_req_xml);
      x_soap_header_xml :=
         x_soap_header_xml.EXTRACT
                     ('/soap:Envelope/soap:Header/child::node()',
                      'xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"'
                     );
                     

      IF x_soap_header_xml IS NOT NULL
      THEN
         soap_header_xml := x_soap_header_xml.getclobval ();
         
         soap_header_xml := '<Response>' || soap_header_xml || '</Response>';
         x_soap_header_xml := XMLTYPE.createxml (soap_header_xml);
         

         /*SELECT EXTRACTVALUE (VALUE (t), '//ServiceErrCode'),
                EXTRACTVALUE (VALUE (t), '//ServiceErrMessage')
           INTO service_error_code,
                service_error_message
           FROM TABLE (XMLSEQUENCE (EXTRACT (x_soap_header_xml, '/'))) t;

         IF service_error_code IS NOT NULL
            OR service_error_message IS NOT NULL
         THEN
            p_output_message_out :=
                           service_error_code || ':' || service_error_message;
            p_response_xml := v_req_xml;
            p_request_xml := v_request_xml;
            RETURN;
         END IF;*/
      END IF;
      
      x_response_xml := XMLTYPE.createxml (v_req_xml);
      abc := x_response_xml.getclobval() ;--Covert XMLTYPE to CLOB to store it as a CLOB. Till here there is no issue, I'm getting the full XML
      sample_procedure('abc = ',abc) ;
      x_response_xml :=
         x_response_xml.EXTRACT
                     ('/soap:Envelope/soap:Body/child::node()',
                      'xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"'
                     );
                     ijk := x_response_xml.getclobval ();
                     sample_procedure('ijk = ',ijk) ;--Covert XMLTYPE to CLOB to store it as a CLOB. Here I'm getting Partial XML
      x_response_xml :=
         x_response_xml.EXTRACT ('/m:getPriceResponse/m:return/child::node()',
                                 'xmlns:m="http://com/bgs/services"'
                                );
      p_response_xml := x_response_xml.getclobval ();
      sample_procedure('p_response_xml =',p_response_xml) ;
     
 end ;