The NewsItem has a public property PublicationDate that you can use to switch the publication date of the item. There is a property DateCreated - gets or sets the date and time the content was created. By default the date created in DateTime.UtcNow;
If you work programmatically you can use the fluent API
App.WorkWith().ContentItems().Where(ci => ci.Id == contentItemId).ForEach(ci =>
// set content item property here.
You can see all properties exposed by ContentItem in our dev manual.
the Telerik team
Do you want to have your say when we set our development plans?
Do you want to know when a feature you care about is added or when a bug fixed?
Telerik Public Issue Tracking
system and vote to affect the priority of the items