Using two drift pins, as adayton advises, is very important if you want to avoid spilling the guts of the gun all over your workspace as you remove and replace the side plate assembly. In the event it all comes apart in your hands and you don't know how these pistols go back together, it really helps to have an exploded assembly diagram handy.

Also....To avoid bending and damaging the side plate assembly and the points where both pins attach, the most common reason for breaking the plate and having to replace the thing, you also have to gradually insert the two drift pins simultaneously into the gun, each one a tiny bit at a time, while gently backing out the side plate assembly's two pins, also a tiny bit at a time.

If you try to drive each pin out individually, or pull the side plate assembly out one pin at a time, the bending force on the side plate itself will often snap the metal or cause irreparable distortion or damage to the part. Take it easy as you back out this side plate assembly, make sure it doesn't bend excessively as it comes out and goes back in, and you won't have to replace it.