curl --request POST \
  --url https://api.example.com/gateway/subscription-payments/cards \
  --header 'Content-Type: application/json' \
  --data '
{
  "merchantReference": "",
  "customerReference": "",
  "authorizationToken": "",
  "holder": "",
  "network": "",
  "first6": "",
  "last4": "",
  "isDefault": true
}
'