Albert Barnes Commentary Esther 8:8

"Write ye also to the Jews, as it pleaseth you, in the king`s name, and seal it with the king`s ring; for the writing which is written in the king`s name, and sealed with the king`s ring, may no man reverse." — Esther 8:8 (ASV)

Write ... as it liketh you ... - (See the Esther 1:19 note. Practically, Ahasuerus reversed the “device” of Haman).