Glass patio door drags when opening and shutting. Believe rollers worn and need
Replacing. Unable to raise door from steel runner at bottom/top. What do I do?

Have you tried adjusting them first? You might get off easy with an adjustment. Both top and bottom. Which coincidently... is what you have to do to get the door out. Only by adjusting it the opposite direction.

Not easy sometimes due to weight and layout. First look at the bottom outside corner for a small hole. Try a screwdriver to adjust the door. Also look for an aluminum lock tab that is screwed to the frame. You remove the tab to lift out the door. Most doors require that the slider is on the outside to remove it by itself. Otherwise, you may need to remove the fixed door to remove the slider. Some doors are removed by adjusting the top and bottom rollers down and then remove. HD and Lowe's usually have the door rollers.