curl --request PATCH \
  --url https://api.ngrok.com/backends/failover/{id} \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --header 'ngrok-version: <ngrok-version>' \
  --data '
{
  "id": "<string>",
  "description": "<string>",
  "metadata": "<string>",
  "backends": [
    "<string>"
  ]
}
'

{
  "id": "<string>",
  "uri": "<string>",
  "created_at": "<string>",
  "description": "<string>",
  "metadata": "<string>",
  "backends": [
    "<string>"
  ]
}