Same for me. I have tried using this card twice today.

First time, I paid the additional 2 mana to prevent one of my creatures being destroyed. Despite the card resolving and the two mana being tapped and spent, I was not given the option to change the target of the spell.

Second time, I paid 5 life to prevent the top three cards being exiled from my library. Despite the card resolving and the five life being spent, I was not able to choose a new target for the spell.

Because the aura is an "enchant creature YOU control". Since you do not take control of the spell, only changing its target, the "you" is still refering to your oppponent. So you can at best redirect the aura onto some other creature under your oponent's control, if there is one. You cannot redirect it to your creatures, since those are illegal targets.

If you try to redirect the trigger, you run into the same problem. The target is a "nonland permanent under your opponent's control". Which again refers to the opponent of the trigger's controller, which is you. So at best you can redirect the trigger to some other nonland permanent of yours, but you cannot redirect it to something under your opponent's control.