The best way to take your book off of sale - is to either mark the title as cancelled, or on the distribution page - un-toggle both these options as well as the territories that it is for sale in.
If you have opted for a publishing project, you will not be able to toggle off 'Sell on The Great British Bookshop' or 'Sell through Bookvault's Global Network', so just ensure that the territories are untoggled.