Sometimes with things like this I add a manual page break (or apply Next Page paragraph formatting) after the troublesome page breaks, then I can delete the breaks without rearranging what follows them.
Another option is to try the Replace dialog. Open the dialog (I use Ctrl + H), click More, then Special, and select Section Break. Or you can just type ^b in the Find What box. It may be best to replace with nothing, then once the troublesome section breaks are gone you can go back and format properly.