I’ve gone to FORMAT with no success
You have tagged common so every program in LibreOffice?! There are no page breaks in Draw or Impress as the slides are already defined each time you create one.
Writer: Place cursor at the end of previous page and press the Delete button.
Calc: View > Page break will allow you see the breaks and, by dragging the separating lines, adjust them to suit. If you are talking about print ranges then Format > Print ranges > Edit will allow you to select what you want to print.