You need to remove the pins from the upper frame. Because they are mounted into a blind hole you need to pound them out through the frame. One the inside you will see a very small nub where the pin was pressed into. I took a 1/16" punch and tapped it out that way. If you dont go crazy it just come out a tiny bit and you can grab the end with a pliers and pull it out, that way you dont destroy the frame. Also watch for the springs on the inside of the arms. They will pop out when you remove the arms and are easy to lose.
Wait there’s springs? There were no springs on my pair