How to update a single sub-object field? C#

Content

I want to update Account.Attributes.AccountLocked field.  What is the best way to do this?

The below code complains about changing NotificationPending field.

Code Snippet

             RightNowService_dev.QueryResultData[] queryObjects = _service_dev.QueryObjects(clientInfoHeader_dev, Strings.selectAccounts, null, 10000);

RightNowService_dev.RNObject[] rnObjects = queryObjects[0].RNObjectsResult;

for (int i = 0; i < rnObjects.Length; i ++)
{                                ((RightNowService_dev.Account)rnObjects[i]).Attributes.AccountLocked = false;
}

_service_dev.Update(clientInfoHeader_dev, rnObjects, options);