How can I create an RMA from a Sales Order using the REST API? Can someone share the correct URL and payload for Postman?

have not tried myself but seems like a transform from SO to RMA.

POST    /record/v1/salesOrder/:id/!transform/returnAuthorization

{   
    "tranDate": "2024-09-05", 
    "item": {
        "items": [
            { 
                "line": 1,
                "item": {"id": "102",
                "quantity": 1,
                "taxcode":710,
                "location":3,
                "amount": 2000
            }
        ]
    }
}

Thank you @Israel Gonzalez,.