When you have a published document and you want it taken offline, go to the review mode of the document and select the 'take offline (request)' action at the top. The editor will receive your request and if he accepts your request, the document will be taken offline.

You can not change a document after you did a request for it for publication or taking offline: your document actions menu will not show any action for it. As soon as the editor handled your request, you can change the document again.

If you just request taking the document offline it will be done as soon as the editor accepts your request. You may want it postponed to some particular moment. Then request scheduling it. A scheduling window will popup just as when scheduling a publication.

It is a good idea to first check if a document is referred to before you request it to be taken offline. Taking offline a document that is referred to by published documents will result in broken links. Readers of your site will not like that. Get the list showing all referring documents. Note that you will not receive a warning if you request to take offline a document that is referred to and neither will the editor handling your request.

Note that the editor can publish or take offline documents without your request. See editor actions.