Once security settings have been applied to a protected file they cannot be changed by users. The settings become part of the document / product and are enforced at all times, even when your customers are using your documents off-line (i.e. they are not connected to the Internet).
If you, as the publisher, want to issue the same document / product with different security settings (copying, printing, etc.) then you must protect the file again with the new settings. You can then send the newly protected file to your customers.
You can also change the number of prints and views on an individual user basis (for files that have limited views/prints), after a document has been published without having to re-protect it. For more information see changing the number of views and changing the number of prints.