Specifies whether or not the modifications in this request and any pending modifications are asynchronously applied as soon as possible, regardless of the PreferredMaintenanceWindow setting for the DB instance. If this parameter is passed as false, changes to the DB instance are applied on the next call to RebootDBInstance, the next maintenance reboot, or the next failure reboot, whichever occurs first. See each parameter to determine when a change is applied. Default: false

public bool ApplyImmediately { get; set; }