Cannot unlink documents when editing an existing page

[OJ423]

I created a new page (terminusdb_docs in TerminatorX)

I liked to an existing body (install as a docker) to be lazy.

I then tried to edit this page as I wanted it to be about Cats rather than Docker.

I cannot unlink the body document from the page. And when I make changes to what is there, for instance, I deleted the markdown and added this,

If you love cats and you love hats, you'll love this.

Bringing you *Cats in Hats*,# Cats in Hats

If you love cats and you love hats, you'll love this.

Bringing you *Cats in Hats*

When submitting, it keeps the existing body and adds the new text to the bottom of it.

In reality, I want to remove the link and create a new body.

When trying to edit the existing linked document I get an API failure:

    "@type": "api:ReplaceDocumentErrorResponse",
    "api:error": {
        "@type": "api:SchemaCheckFailure",
        "api:witnesses": [
            {
                "terminusdb:///documentation/schema#media": {
                    "@type": "required_field_does_not_exist_in_document",
                    "document": {
                        "@type": "terminusdb:///documentation/schema#Media",
                        "terminusdb:///documentation/schema#title": {
                            "@type": "Title",
                            "value": "Test 12454534"
                        }
                    },
                    "field": "terminusdb:///documentation/schema#alt"
                }
            }
        ]
    },
    "api:message": "Schema check failure",
    "api:status": "api:failure"
}```