---
title: "Change reconciliation"
description: "Match detected drift to approved change requests automatically."
product: "Guardian"
edition: "Essentials"
type: "overview"
url: "https://docs.cloudhouse.com/guardian/essentials/change-reconciliation/"
---
# Change reconciliation

Change reconciliation matches the drift Guardian detects against approved change requests in ServiceNow. Drift covered by an approved change is reconciled for you, so what's left on Detected Drift is change nobody approved.

Applies to: `Guardian Essentials` `Additional capability` `ServiceNow`

Bringing CIs into Guardian works on every edition. Change reconciliation is an additional capability, set up through your service management tool.

## How it works

1. **Change requests sync from ServiceNow** every 15 minutes. All open change requests are pulled, and matched to Guardian CIs through their CMDB CI. Setup helps you match your CIs.
2. **Guardian captures scans before and after change windows:** a baseline snapshot as the window opens, and a post-change scan when it closes.
3. **The change's lifecycle completes in ServiceNow:** approval, implementation, review and closure. This can take hours or days, depending on your process.
4. **Reconciliation results appear on Detected Drift.** Guardian reconciles each change request automatically, as matched, partially matched or unmatched, with a full audit trail.

Reconciliation runs in the background. While it's on, you can't select individual changes to reconcile by hand.

!!! warning "Review what's flagged"
    A change can be reconciled against a change request even when what actually changed doesn't match what the change request describes. For example, a CI may be listed on the change request while the change made to it was unrelated. Review the items Detected Drift flags to catch these.

## Set it up

See [Set up with ServiceNow](https://docs.cloudhouse.com/guardian/essentials/change-reconciliation/servicenow/index.md).