切换 (qiē huàn) means to switch between modes, systems, or data streams — like toggling between night mode and day mode. It's more specific than 转换 (zhuǎn huàn), which means to convert or transform from one state to another (e.g., convert currency, transform energy). Use 切换 when flipping between options; use 转换 when changing the form or nature of something.