curl --request PUT \
  --url https://api.sanka.com/v1/public/purchase-orders/{purchase_order_id} \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "external_id": "<string>",
  "contact_id": "<string>",
  "contact_external_id": "<string>",
  "company_id": "<string>",
  "company_external_id": "<string>",
  "date": "<string>",
  "status": "<string>",
  "currency": "<string>",
  "notes": "<string>",
  "tax_rate": 123,
  "tax_option": "<string>",
  "total_price": 123,
  "total_price_without_tax": 123
}
'

{
  "ok": true,
  "status": "<string>",
  "external_id": "<string>",
  "purchase_order_id": "<string>",
  "ctx_id": "<string>"
}