Unable to upload WTDocument content via rest

[NN_9148331]

I am getting the following when I try to run UploadStage3Action

{
    "error": {
        "code": null,
        "message": "Content holder must be checked out for content upload"
    }
}

Not sure what I am doing wrong.

Here is what I am passing in the body for UploadStage3Action

{
    "ContentInfo" : [
        {
        "StreamId" :726306,
        "EncodedInfo" : "726306%3A5184%3A779025%3A726306%3ANONE%3A1",
        "FileName" : "TOC.json",
        "PrimaryContent" : true,
        "MimeType" : "text/json",
        "FileSize" : 5184
        } 
    ]
}

URL used : https://<WCURL>/Windchill/servlet/odata/DocMgmt/Documents('OR:wt.doc.WTDocument:15196389')/PTC.DocMgmt.UploadStage3Action

For UploadToCache Server 

I used the following body data

-----------------------------boundary
Content-Disposition: form-data; name="Master_URL"

https://<WCURL>/Windchill/servlet/WindchillGW
-----------------------------boundary
Content-Disposition: form-data; name="CacheDescriptor_array"

726306:726306:726306
-----------------------------boundary
Content-Disposition: form-data; name="0000006124"; filename="TOC.json"

eyJUYWJsZU9mQ29udGVudHMiOn#TRUNCATED_DATA##
-----------------------------boundary--
           

Here is data obtained from UploadStage1

{
    "@odata.context": "$metadata#CacheDescriptor",
    "value": [
        {
            "FileNames": [
                726306
            ],
            "FolderId": 779025,
            "ID": null,
            "MasterUrl": "<WCURL>/Windchill/servlet/WindchillGW",
            "ReplicaUrl": "https://<WCURL>/Windchill/servlet/WindchillGW/wt.fv.uploadtocache.DoUploadToCache_Server/doUploadToCache_Master?mk=wt.fv.uploadtocache.DoUploadToCache_Server&VaultId=746601&FolderId=779025&SSC=1&CheckSum=1452612&sT=1662971140&sign=LVngsXMgfu0R%2BRUmzVlXcmLX2%2FmQeaaXSwnyM5o0IEk%3D&site=https%3A%2F%2<WCURL>%2FWindchill%2Fservlet%2FWindchillGW&AUTH_CODE=HmacSHA256&isProxy=true&delegate=wt.fv.uploadtocache.DefaultRestFormGeneratorDelegate",
            "StreamIds": [
                726306
            ],
            "VaultId": 746601
        }
    ],
    "@PTC.AppliedContainerContext.LocalTimeZone": "UTC"

[avillanueva]

Does this article make sense to you?

https://www.ptc.com/en/support/article/cs305415?language=en&posno=2&q=update%20document%20via%20REST&source=search

Indicates first step is to check out the document which is what the error message is saying.