How to schedule maintenance of unknown snapshots
To schedule maintenance of snapshots that belong to a volume:
From the Main Menu, select Snapshots.
Click the Snapshot Maintenance option located above the snapshots list.
In the new window, identify the EBS volume to schedule maintenance for.
From the menu, select Schedule Maintenance.
Select maintenance options and click Save.
To learn more about Snapshot Maintenance options, please go to: How to schedule maintenance of Snapshots