Yes, and in many homes it is one of the most useful upgrades. The lever lock is the old type, with the long key that has teeth at the tip, and it is quite a lot easier to open than a cylinder lock.
By converting it to a European cylinder you gain security and you can choose whichever cylinder you like: anti-bump, anti-snap or high security. And if you ever lose your keys, changing the cylinder is enough.
Depending on the door, the lock you have is adapted or it is replaced entirely with a cylinder lock. On older security doors, of which there are plenty around here, it is a very common job.
Send us a photo of the lock from the outside and of the edge of the door and we will tell you what can be done. It is all in lever lock to cylinder conversion.