curl --request PUT \
  --url https://api.hubapi.com/content/api/v2/pages/{page_id}/buffer \
  --header 'Content-Type: application/json' \
  --data '
{
  "widgets": {},
  "widget_containers": {}
}
'

{
  "id": 352531415,
  "name": "Contact Us",
  "slug": "my-api-demo-page-slug",
  "html_title": "The API Test Page",
  "has_user_changes": true,
  "updated": 1441239877000
}