を交換した

exchanged; replaced

→ を
phrase Rare #39,044
exchanged; replaced The past form of 交換する, meaning to exchange or replace something. The object marked by を is what was exchanged or replaced.
JA: 私は、彼と切手を交換した。
EN: I exchanged stamps with him.

私は彼と切手を交換した

I exchanged stamps with him.

彼は古い車新しい車を交換した

He replaced his old car with a new one.

社員達は会議で意見を交換した

The employees exchanged opinions at the meeting.

エンジンを交換したからだ

Because I replaced the engine.

— エリート・スクワッド (2007)