Hmmm I think through his omniscience, it's more of He knows which choices He can make, as opposed to will make because of the choice factor. And even if it is "will" make, why can't he change his future choices?
Sorry, I just really don't see the clash.
OMNISCIENCE = KNOWS EVERYTHING
And that means HE KNOWS WHAT HE WILL DO,not only his options BUT WHAT HE WILL CHOSE.So when i ask if he can change the future WHICH HE ALREADY KNOWS i ask if he can change the way he KNOWS things will be.If he does that then he DIDN'T KNOW IT IN THE FIRST PLACE.
He can't have both attributes
(it's just illogical )

