Rub Rail Removal

I began to remove my rub rail today for two reasons: Gelcoat restoration and rope replacement. A section of the original rope on the stern was missing so I began removing the exposed rub rail attaching screws, no problem. The process ended abruptly because access to the rail attaching screws ended. Does anyone have any experience removing the rub rail and/or replacing the rope? How did you remove the rope from it's groove to gain access to the mounting screws or to replace it? Did you pull it out/directly away from the boat through the small slit or did you "snake" it out by pulling it all the way through? The black rub rail seems hard and maybe brittle. Has anyone cracked theirs doing this? Thank you!

Thank you!!