Even though most serrated bread knives are razor sharp and last long, it’s still possible to sharpen them. If you notice it has started getting blunt, try to sharpen it immediately.
However, you shouldn’t do this often. The pointed teeth of a serrated knife do the majority of the work.
The blade is serrated, which helps it not to be exposed to friction, which makes it stays sharper for a longer time. Therefore the reason why these knives are sharp is due to their serrated blades.