curl --request GET \
  --url https://api.vantage.sh/v2/managed_accounts \
  --header 'Authorization: Bearer <token>'

{
  "links": {
    "self": "https://api.vantage.sh/v2/managed_accounts",
    "first": "https://api.vantage.sh/v2/managed_accounts?page=1",
    "next": null,
    "last": "https://api.vantage.sh/v2/managed_accounts?page=1",
    "prev": null
  },
  "managed_accounts": [
    {
      "token": "acct_be30cfd09cf0b3c5",
      "name": "Rep. Gavin Berge",
      "contact_email": "gavin_berge_rep@orn.net",
      "parent_account_token": "acct_f95654a3aefab4b7",
      "access_credential_tokens": [],
      "billing_rule_tokens": [],
      "email_domain": null
    }
  ]
}