If I were Omnipotent, I'd kill myself.

A god who is both omnipotent and omnipresence is contradictory.

Sometimes this contradiction is hard to see, so let me show you a different way to understand it.

Think of "seeing the future" as if you were watching a VHS tape. Except, you're watching it in reverse.
Let's say it's a tape of a railroad trip.
You see yourself arrive at your San Francisco destination.
As the tape reverses, you see yourself get on the train.
After a few min, you board at San Jose.
As you approach the ticket stand, What do you think you said to the ticket vendor?
Would it matter if you said you wanted a ticket to Oakland?
No, it wouldn't matter, you know you will end up at San Francisco for one reason or another. You already know the destination despite the decision.

To "change the future" we'll have to look at a situation where we can see and change the actions dynamically, this is done by a domino rally pattern that forks into two.
However, there is a switch that only allows one of those forks to go on, the other goes in another direction. If you place a red piece at the end of the right fork, knowing it will be knocked down; you are basically seeing the future.

However, because you want to change the future, you switch it to the left position, when you set it off, the red one will NOT be knocked down, invalidating your red domino prediction. Therefore you did not see the actual future.

Some would argue, What if you switch the red domino to the left branch, it'd work. It's a short sighted argument. You really haven't changed the future, you've just stepped back to square one.

Some would argue, maybe omnipotence is knowing all possibilities of the future. Therefore it wouldn't be contradictory to choose one of those as it's actual event. Again, it is a short sighted argument. Once one of these possibilities is chosen, all other possibilities are false futures, and again you're back to square one.
There still is only one red domino.

If you can see the future, you can not change it.
If you can change the future, you haven't really seen the future.

Maybe your definition of omnipresence is that of the now, not of the future. Unfortunately, that's not very all-knowing.