Zero Gravity

[exodia]

Zero Gravity:
Change the battle positions of all face-up monsters on you and your opponent's sides of the field.

So the question is when I avtivate it Do I have to change my opponets monster that was in defense mode or do i get to chose whether or not to.
Also do i have to change the position of my moster?

 

[densetsu_x]

Change the battle positions of all face-up monsters on you and your opponent's sides of the field.

You have no choice in the matter when you activate that card. If it's face up on the field, you change it from defense to attack position or vice-versa.

 

[exodia]

Thank you for the answer