比較N1
〜と（は）打って変わって
completely different from... / a complete change from...
Structure
N + とは打って変わって
Explanation
N + とは打って変わって: completely different from the previous state.
Examples
昨日とは打って変わって、今日はとてもいい天気だ。
Completely unlike yesterday, today the weather is beautiful.
彼は入社してからというもの、以前とは打って変わって真面目になった。
Since joining the company, he's become a completely different, serious person.
Note
Emphasizes a dramatic change, contrasting two completely different states.