idiom · to change the outward appearance of something while its essence remains the same, often used derogatorily to imply deception

这个方案只是改头换面，核心内容一点没变。

idiom · to undergo a thorough or significant change for the better, often used in a non-derogatory sense

经过重新装修，这家旧书店改头换面，成了网红打卡地。