curl --request PUT \
  --url https://app.herondata.io/api/integration_links/{item_id} \
  --header 'Content-Type: application/json' \
  --header 'x-api-key: <api-key>' \
  --data '{
  "end_user": {
    "access_token": "access-sandbox-de3ce8ef-33f8-452c-a685-8671031fc0f6"
  }
}'

{
  "integration_link": {
    "created": "2020-01-01T00:00:00Z",
    "item_id": "M5eVJqLnv3tbzdngLDp9FL5OlDNxlNhlE55op",
    "last_successful_sync": "2020-01-01T00:00:00Z",
    "last_updated": "2020-01-01T00:00:00Z",
    "status": "active",
    "status_message": "[ITEM_LOGIN_REQUIRED] the login details of this item have changed (credentials, MFA, or required user action) and a user login is required to update this information. use Link's update mode to restore the item to a good state",
    "type": "plaid_assets_report"
  }
}