Megastar 45ACP rear sight problem

[tenforty]

I have a Megastar which I purchased new in 92. I haven't out for a few years until recently. I noticed that the rear sight was loose. I was wondering if anyone out there has experience with this pistol and can tell me how to remove the rear sight. I know there is a pin with a spring that holds it in place. I do not see anyway to get to the pin to release it. Any help would be appreciated.