There is no specific approval feature in the help desk at the moment. This feature is on our customer wish list, but we do not have an estimated release date for it unfortunately. You can create an approval checkbox with the custom ticket field feature, but there is no way to prevent agents from editing the ticket until the checkbox is ticked.
I would recommend sending any further 6.0 related questions to support@lansweeper.com and including "beta" in the title of your message. We haven't officially released 6.0 yet, so we're mostly answering questions via email.