curl --request POST \
  --url https://eu1.api.matillion.com/dpc/v1/projects/{projectId}/variables/{variableName}/environment-overrides \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "overrides": [
    {
      "environmentName": "<string>",
      "value": "<unknown>"
    }
  ]
}
'

{
  "failedOverrides": [
    {
      "environmentName": "<string>",
      "reason": "<string>"
    }
  ],
  "successfulOverrides": [
    {
      "environmentName": "<string>",
      "value": "<unknown>"
    }
  ],
  "type": "NUMBER",
  "variableName": "<string>"
}