ServiceNow exposes a standard WSDL file for all Table API web services.

Namespaces are already defined by ServiceNow instance.  However, you may want to use a specific WSDL file specifications for a custom SOAP Web Service running in ServiceNow. This article shows the available alternatives.

Any supported release.

It is possible to personalize the web service in ServiceNow up to certain level, but only programmatically. Custom scripts and web services are required.
Here is the information that can be helpful for this purpose.

a) Custom WSDL

ServiceNow allows to create and publish your own WSDLs to expose a SOAP service by using "scripted SOAP services".
The WSDL can be tailored to your needs and may expose the namespaces that you want (not generated by ServiceNow engine).

To use a Static WSDL you need three different objects:

- A scripted web service
- A custom script includes that handles the web service request.
- A WSDL

This approach may resolve the namespace requirements. Please refer to the documentation in this link:

Static WSDL
https://docs.servicenow.com/bundle/orlando-application-development/page/integrate/inbound-soap/task/t_CreateAStaticWSDL.html

b) Custom Scripted Web Service Response.

You have also the possibility to have control over the XML payload of a SOAP response returned by a scripted web service, by creating the XML object that you want to return as response.

Please read the following documentation and example:

Customize response
https://docs.servicenow.com/bundle/orlando-application-development/page/integrate/inbound-soap/task/t_CustomizeResponse.html

c) Custom HTTP Headers

The response http headers returned by ServiceNow for scripted SOAP web services cannot be customized.