curl --request POST \
  --url https://api.example.com/concat/assign-ism \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "concatCode": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
  "ismCode": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
  "languageId": null,
  "leadingConjunctionId": null
}
'

{
  "success": true,
  "data": "<unknown>"
}