they can work on it without taking it down. the design is done offline and then you upload the files to whatever server you have hosting the site and it replaces or updates the page immediately without having to actually remove something to change it. i cant imagine needing to take a non-indexed page down for the sole reason of updating or working on it. i also am not sure why it would be taken down unless maybe they didn't want that info to be public yet and realized the public had found the page.
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