To turn off Vanish Mode on Instagram, open the chat where it's active. You'll know it's on if you see the screen shaded or messages disappearing. Swipe up from the bottom of the chat or tap the "Turn Off Vanish Mode" button at the top. This action will immediately switch off Vanish Mode, and your messages will stay in the chat history, visible for both you and the person you're chatting with. Remember, any messages sent while Vanish Mode was active won't reappear; only new messages sent after turning it off will stay.