curl --request DELETE \
  --url https://sandbox.voice.miraiminds.co/v2/callbacks/{callback_id} \
  --header 'Authorization: Bearer <token>'

import requests

url = "https://sandbox.voice.miraiminds.co/v2/callbacks/{callback_id}"

headers = {"Authorization": "Bearer <token>"}

response = requests.delete(url, headers=headers)

print(response.text)

const url = 'https://sandbox.voice.miraiminds.co/v2/callbacks/{callback_id}';
const options = {method: 'DELETE', headers: {Authorization: 'Bearer <token>'}};

fetch(url, options)
  .then(res => res.json())
  .then(json => console.log(json))
  .catch(err => console.error(err));

{
  "error": {
    "code": "not_found",
    "message": "no scheduled callback cbk_5f2a9c0e71d34b8a6e19c047"
  }
}