const options = {method: 'PUT', headers: {Authorization: 'Bearer <token>'}};

fetch('https://api.thanks.io/api/v2/orders/{orderId}/cancel', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

{
  "order": {
    "id": 42708,
    "user_id": 2,
    "sub_account_id": null,
    "type": "postcard",
    "message": "Hey %FIRST_NAME%!,\n\nTHANK YOU for allowing us the opportunity to HELP you with your plan!",
    "message_template_id": 116,
    "image_template_id": 195091,
    "style": 1,
    "handwriting_color": "#000001",
    "font_size": "auto",
    "realism": 40,
    "size": "4x6",
    "addons": {
      "standardmail": "on"
    },
    "front_image": "https://d2md0c8rpvzmz5.cloudfront.net/letter-backgrounds/bg0.png",
    "back_image": "",
    "preview_images": [
      "https://d2md0c8rpvzmz5.cloudfront.net/letter-backgrounds/bg0.png"
    ],
    "thumbnail_images": [
      "https://d2md0c8rpvzmz5.cloudfront.net/letter-backgrounds/bg0.png"
    ],
    "high_quality_preview": "",
    "custom_background_url": null,
    "additional_letter_pages": null,
    "skip_creative_generation": 0,
    "giftcard_brand": null,
    "giftcard_image": null,
    "giftcard_amount": null,
    "qrcode_url": null,
    "mailing_list_ids_used": "3047",
    "total_estimated_recipients": 1,
    "authorization_total": 73,
    "total_recipients": 1,
    "grand_total": 73,
    "status": "fulfilled",
    "method": "drip",
    "email_cc": null,
    "total_scans": 0,
    "unique_scans": 0,
    "last_scan": null,
    "return_name": null,
    "return_address": null,
    "return_address2": null,
    "return_city": null,
    "return_province": null,
    "return_postal_code": null,
    "display_addons": "+Standard Mail",
    "display_status": "Fulfilled",
    "display_trigger": "Campaign",
    "display_type": "Postcard-4x6",
    "giftcard_brand_longname": ""
  }
}