curl --request POST \
  --url https://app.flowglad.com/api/v1/subscriptions/{id}/cancel \
  --header 'Authorization: <api-key>' \
  --header 'Content-Type: application/json' \
  --data '{
  "cancellation": {
    "timing": "<string>"
  }
}'

{
  "subscription": {
    "id": "<string>",
    "createdAt": 0,
    "updatedAt": 0,
    "livemode": true,
    "startDate": 0,
    "customerId": "<string>",
    "organizationId": "<string>",
    "status": "trialing",
    "defaultPaymentMethodId": "<string>",
    "backupPaymentMethodId": "<string>",
    "trialEnd": 0,
    "currentBillingPeriodStart": 0,
    "currentBillingPeriodEnd": 0,
    "metadata": {},
    "canceledAt": 0,
    "cancelScheduledAt": 0,
    "cancellationReason": "<string>",
    "replacedBySubscriptionId": "<string>",
    "isFreePlan": true,
    "priceId": "<string>",
    "runBillingAtPeriodStart": true,
    "interval": "day",
    "intervalCount": 123,
    "billingCycleAnchorDate": 0,
    "name": "<string>",
    "renews": true,
    "current": true
  }
}