What happen if SDHC card get write error (damaged cell / bad sector) ?

Whole card is unusable (to trash, all data written to that sector now and in future will be lost) ? or rewrite sector (flash memory get corrupted when writing so maybe have any function to check if sector was written successfully) to another and mark as fault as unusable what will be seen as reduction of capacity but no data lost.

I have to do some research about SD card-s on disk less machines.

regards