Changing Pre-Order?

Sorry if this is the wrong place for this, I figured that it was best to put it here. I pre-purchased BL3’s default edition through the Epic Games store for PC, and I was wondering if it was possible to upgrade the package? $100 was too much for me to put out at once, so is it possible to take my $60 purchase, add another $40 to it and get the pack with the season pass and skins?