import requests

url = "https://api.example.com/api/v1/pending-operations/{pending_operation_id}/reject"

payload = { "reason": "<string>" }
headers = {"Content-Type": "application/json"}

response = requests.post(url, json=payload, headers=headers)

print(response.text)

{
  "result": {
    "pending_operation_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
    "status": "pending",
    "transaction_id": "<string>",
    "request_id": "<string>",
    "idempotent": false
  },
  "success": true,
  "suggestion": "",
  "message": "",
  "meta": {
    "total": 123,
    "offset": 123,
    "limit": 123,
    "has_more": true,
    "after": "<string>",
    "before": "<string>"
  }
}