Is there a particular set order you like to use, for example sorting by pinyin/jyutping? If so, you can create a new category, do a search (magnifying glass icon in Organize) for cards in the old category, set the sort order for that search to whatever order you want to use, and add all of those search results in bulk to the new category; they should come through in that new category in the correct order.
(if you're using the free 'lite' version of our flashcard system which doesn't have a search screen, you can export your flashcards to a text file, reorder them in your favorite text editor, delete the old category, and then reimport them)
(if you're using the free 'lite' version of our flashcard system which doesn't have a search screen, you can export your flashcards to a text file, reorder them in your favorite text editor, delete the old category, and then reimport them)
Best option I can think of in that case would be to create a new category and then add your old cards to the new category in those pairs. Either that or edit them in a text file - if you reimport them into a new category (edit the category name at the top of the export file) without deleting the old one then the newly imported category should link to your existing cards rather than creating new ones.