代 + 之 + 的是 + Noun
The noun 代 (dài) can mean "replacement" or "in place of." It often appears in the fixed expression 取而代之 or 代之的是, meaning "instead" or "in its place." For example, 代之的是 means "in its place is."
他不想亲自去,就让同事代之。
tā bù xiǎng qīn zì qù, jiù ràng tóng shì dài zhī.
He didn't want to go in person, so he had a colleague go in his place.
旧的方案被取消了,取而代之的是全新的计划。
jiù de fāng àn bèi qǔ xiāo le, qǔ ér dài zhī de shì quán xīn de jì huà.
The old plan was canceled and replaced with an entirely new one.
代之的是一种更高效的管理方式。
dài zhī de shì yī zhǒng gèng gāo xiào de guǎn lǐ fāng shì.
What replaced it was a more efficient management approach.