u/Packet-Possum

I am trying to replace this toilet seat with a soft close one.

The fastening on the bottom are not coming off. the one on the left continuously spins without miving down the thread, the one on the right is stuck and will only do a 1/4 turn twist.

I cant twist it off with pliers as the ends knock the porcelain and prevent rotation.

Any ideas on how to get this thing off?