IBM GraphDB - Update a vertex property, selecting vertex by vertex ID.

update_vertex_property.json

{
    "properties": 
    {
        "name": "Your new name",
        "age": 21,
        "tags": "TAG1"
    } 
}

USAGE.txt

Here, you hit the vertex endpoint, supplying VERTEX_ID in the URL.
DOCUMENTATION: https://ibm-graph-docs.ng.bluemix.net/api.html#vertex-apis

Currently, something like:
-HTTP: POST
-URL: https://ibmgraph-alpha.ng.bluemix.net/$APIURL/$GRAPHNAME/vertices/$VERTEXID
-BODY: update_vertex_property.json