Locking Page Templates
Before editing a page template, you should lock the page template. Locking prevents the page template from being edited by other users in parallel. The page template lock can be released manually. It is released automatically after the configured lock interval has expired. For details about how to configure the page template lock interval, see Defining Content Lock Period.
Basically, there are two ways to lock page templates: either directly from the page template list or tree, or via the Page Template detail view.