'Reverse' in the Bible

Behold, I have received commandment to bless: and he hath blessed; and I cannot reverse it.

And said, If it please the king, and if I have found favour in his sight, and the thing seem right before the king, and I be pleasing in his eyes, let it be written to reverse the letters devised by Haman the son of Hammedatha the Agagite, which he wrote to destroy the Jews which are in all the king's provinces:

Write ye also for the Jews, as it liketh 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.