curl --request PATCH \
  --url https://api.zenskar.com/entitlements/{entitlement_id}/customer/{customer_id}/{ec_id} \
  --header 'Content-Type: application/json' \
  --header 'organisation: <api-key>' \
  --header 'x-api-key: <api-key>' \
  --data '
{
  "entitlement": "<string>",
  "customer": "<string>",
  "expiry_at": "2023-11-07T05:31:56Z",
  "active_from": "2023-11-07T05:31:56Z",
  "quantity": 123,
  "quantity_used": 123
}
'

{
  "id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
  "entitlement": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
  "customer": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
  "expiry_at": "2023-11-07T05:31:56Z",
  "active_from": "2023-11-07T05:31:56Z",
  "quantity": 123,
  "quantity_used": 123,
  "created_at": "2023-11-07T05:31:56Z"
}