Avoid Scheduled Maintenance window from affecting my Availability SLA reports
By default, when SLA reports are generated, monitors under maintenance will not be considered as 'Up' or 'Available'. - Log In to Site24x7.
- Navigate to Admin > Report Settings > Customize Report.
- Toggle to Yes near the In reports, treat monitors as UP during maintenance period field.

To change an outage to scheduled maintenance after it has occurred,
refer here.