SOAP Web service call out with wsdl

Good day! Does anyone know how to call a webservice without the wsdl?

This is the sample wervice:

<?xml version="1.0" encoding="utf-8"?>
<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/">
<s:Header>
<h:ContractVersion xmlns:h="http://schemas.SOMEWHERE.com/WebServices">340</h:ContractVersion>
</s:Header>
<s:Body>
<LogonRequest xmlns="http://schemas.SOMEWHERE.com/WebServices/ServiceContracts/SessionService">
<logonRequestData xmlns:a="http://schemas.SOMEWHERE.com/WebServices/DataContracts/Session"

xmlns:i="http://www.w3.org/2001/XMLSchema-instance">
<a:DomainCode>def</a:DomainCode>
<a:AgentName>NAME</a:AgentName>
<a:Password>PASSWORD</a:Password>
<a:LocationCode i:nil="true"></a:LocationCode>
<a:RoleCode i:nil="true"></a:RoleCode>
</logonRequestData>
</LogonRequest>
</s:Body>
</s:Envelope>