Removing rear seat headrests
If you need more room to fold the rear seats, you can remove the outer seats' headrests.

Press and hold the button on the base of the right support.
Move the headrest upwards until it detaches from the seat.
Warning
Never drive with a passenger sitting in a seat without an attached and properly adjusted headrest. This can lead to fatal or serious personal injury.
Make sure to stow the removed headrests properly while the rear seats are folded down. Always reattach the headrests once you raise the seats again.