Closures are for anything that does not repeat every week: a public holiday, a week away, a training afternoon, an unexpected day off. Go to Closures in the admin.
For a pattern that repeats — every Monday, or a standing lunch break — change the working hours instead. See Set your opening hours.
Whole business or one person
A closure can apply to the entire business or to a single provider. Closing the business hides every time in that range from your booking site. Closing one provider leaves your other people bookable, which is what you want for one person's leave.
You can close a whole day or part of one, so "closing at 14:00 this Friday" is a closure too, not a permanent hours change.
Bookings already in the range
If bookings already exist inside the range you are closing, Rantevo will not cancel them automatically.
Instead it shows you exactly which bookings are affected and asks what to do with each. You can cancel them, and if you do, the customer is notified automatically.
So add closures before the dates fill up. The earlier you enter one, the fewer bookings you will have to deal with by hand.
After a closure ends
Nothing to undo. Availability returns by itself once the date range is past, and you can delete a closure at any time to reopen those dates immediately.