curl --request POST \
  --url https://api.voice.ai/agent/v1/agent/release-phone-number \
  --header 'Content-Type: application/json' \
  --data '
{
  "phone_number": "<string>",
  "provider": "twilio"
}
'

{
  "phone_number": "<string>",
  "status": "<string>"
}