it can be done-- just use plastic or wood shims to assist-- don't use metal putty knives .
cut the sealant around both sides of the glass-- slide a razor blade following the glass , work the lip of the gasket bending it back/forth.
I start on the top corner-- which ever side is the easiest to start. once you get the glass coming forward & a shim in place it will move rather quickly.
the sun & heat is your friend.
Lawrence