curl --request POST \
  --url https://app.herondata.io/api/end_users/{end_user_heron_id}/funder_submissions/{submission_heron_id}/submit_to_funder/ \
  --header 'Content-Type: application/json' \
  --header 'x-api-key: <api-key>' \
  --data '
{
  "use_sandbox": true
}
'

{
  "submission_heron_id": "<string>"
}