Empty ducts for fiber optic "filled in"

Yes, but how do the fiber optic cables get into the apartments now? There wouldn't have been any need for empty conduits if they are going to be filled in. What should have been done correctly then? Thank you very much for a hint.

Yes, but how do the fiber optic cables get into the apartments now?

How about simply pulling them through the conduits where the telephone cables are currently located?

There wouldn't have been any empty conduits needed if these are then filled in.

How do you actually fill in empty conduits in a multi-family house?

What should have been done correctly then? Many thanks for a hint.

All other cables were not laid in conduits, or were they all also "filled in"? P.S. Another possible solution is then only to re-lay through new chases in the walls...