Changing one's mind infers a time line. I think you're talking about an all knowing God that isn't also timeless VOID/ that knows everything from a fixed point in time. If God is timeless then his mind exists in all time at once/ He knows all things at all time at once. He cannot change his mind because his mind would exist at an end state of knowledge. Hence all knowing.
Changing his mind is not something a timeless God would ever need to do. Therefore it doesn't challenge his omnipotence.
Changing his mind is not something a timeless God would ever need to do. Therefore it doesn't challenge his omnipotence.
