curl --request POST \
  --url https://api.example.com/api/v1/subscriptions/{subscription_id}/cancel \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "effective_date": "2023-12-25",
  "reason": "<string>"
}
'

{
  "subscription": {
    "auto_advance_invoices": true,
    "billing_day_anchor": 123,
    "charge_automatically": true,
    "created_at": "2023-11-07T05:31:56Z",
    "current_period_start": "2023-12-25",
    "customer_id": "<string>",
    "customer_name": "<string>",
    "id": "<string>",
    "mrr_cents": 1,
    "net_terms": 1,
    "plan_id": "<string>",
    "plan_name": "<string>",
    "plan_version": 1,
    "plan_version_id": "<string>",
    "start_date": "2023-12-25",
    "activated_at": "2023-11-07T05:31:56Z",
    "billing_start_date": "2023-12-25",
    "current_period_end": "2023-12-25",
    "customer_alias": "<string>",
    "end_date": "2023-12-25",
    "invoice_memo": "<string>",
    "payment_methods_config": {
      "config": {
        "card": {
          "enabled": true
        },
        "direct_debit": {
          "enabled": true
        }
      }
    },
    "plan_description": "<string>",
    "purchase_order": "<string>",
    "trial_duration": 1
  }
}