Resets an attribute of an instance to its default value. To reset the kernel or ramdisk, the instance must be in a stopped state. To reset the sourceDestCheck, the instance can be either running or stopped.

The sourceDestCheck attribute controls whether source/destination checking is enabled. The default value is true, which means checking is enabled. This value must be false for a NAT instance to perform NAT. For more information, see NAT Instances in the Amazon VPC User Guide.