С modify_cluster_maintenance()
:
response = client.modify_cluster_maintenance(
ClusterIdentifier='string',
DeferMaintenance=True|False,
DeferMaintenanceIdentifier='string',
DeferMaintenanceStartTime=datetime(2015, 1, 1),
DeferMaintenanceEndTime=datetime(2015, 1, 1),
DeferMaintenanceDuration=123
)