Press Ctrl+Shift+8 to show paragraph marks
Go to the extra page
Select and delete blank paragraphs, page breaks, or section breaks
Remove any hidden tables, images, or text causing the page
If the page is after a table, click after the table and delete extra paragraph marks
Use Backspace or Delete to remove unwanted content
Check for a manual page break and delete it
If needed, reduce the font size of the final paragraph mark to 1 pt
Open the Navigation Pane and verify the page is gone
Save the document