curl --request POST \
  --url https://api.example.com/v1/exchange_price \
  --header 'Content-Type: application/json' \
  --header 'X-API-Key: <api-key>' \
  --data '
{
  "booking_ref": "JNK-A0AUR2",
  "last_name": "Carrard",
  "offer_id": "exch_offer_3c1a9f"
}
'

{
  "payment_outcome": "additional_payment_due",
  "fare_difference": {
    "value": 318.4,
    "amount": 123,
    "currency": "USD",
    "decimal_places": 2
  },
  "penalty_amount": {
    "value": 318.4,
    "amount": 123,
    "currency": "USD",
    "decimal_places": 2
  },
  "total_due": {
    "value": 318.4,
    "amount": 123,
    "currency": "USD",
    "decimal_places": 2
  },
  "total_refund": {
    "value": 318.4,
    "amount": 123,
    "currency": "USD",
    "decimal_places": 2
  },
  "session_reference": "exch_7a1c93f0",
  "expires_at": "2026-06-01T13:04:56.000Z",
  "warnings": [
    "<string>"
  ]
}