How to convert a SOAP Webservice to a RESTful webservoce


We have a scenario where we are required to use our existing asset i.e. the provider , XSD etc. And expose a RESTful webservice which is also exposed as a SOAP webservice currently. I understand that RESTful webservice do not have a well structured contract like a WSDL . But I am wondering how do I leverage my assets - especially the XSD or ISSchema or the document to generate a sample JSON message and share with the consuming party. I am fine with building the service by itself , but trying to find a best way to communicate my contract to the consumer.