Another common way ... paint lines or caulk with a utility knife. Remove the stops with a moulding pry bar. You may need a rubber mallet to wedge the pry bar between sash and stops. Detach sash cords ...

Also, use binoculars to make sure the window panes and frames are intact and won’t rain down loose pieces on you. While you’re looking, check for putty that needs to be replaced, necessary paint ...