I can't find any such passage in the Book of Esther. Can you cite the chapter and verse?
According to the New American Bible, Chapter 4 footnotes:
* [4:8] The Greek text adds the following to Mordecai’s message to Esther: “Remember the days of your lowly estate, when you were brought up in my charge; for Haman, who is second to the king, has asked for our death. Invoke the Lord and speak to the king for us: save us from death.”