Minolta 7000i Help on changing focus screen

I have recently been buying some more 35mm film kit on eBay and acquired a good example of the Minolta 7000i, which has the benefit of the L type focus screen. Now I know that you can change the screens on that camera and the provide tweezers to do it. But for the life of me I can't see how you remove the screen, anybody done if before that can help?

Thanks

Jim