If you want to be able to change the Web Service URL of a SOAPRequest node without editing the WSDL, set it through the LocalEnvironment. Just set the path LocalEnvironment.Destination.SOAP.Request.Transport.HTTP.WebServiceURL to the wanted address. For example, use a compute node:

SET OutputLocalEnvironment.Destination.SOAP.Request.Transport.HTTP.WebServiceURL = 'http://seybold.se/ws.asmx';