curl --request POST \
  --url https://api.example.com/v1/voiceai/outbound-call \
  --header 'Content-Type: application/json' \
  --header 'x-api-key: <api-key>' \
  --data '
{
  "agent_id": "<string>",
  "phone_number_id": "<string>",
  "to_phone_number": "<string>"
}
'

{
  "success": true,
  "conversation_id": "<string>",
  "message": "Success",
  "call_sid": "<string>"
}