How does the semiconserative nature of dna replication prevent and correct potential mutations?

DNA polymerase builds the complementary strand on the template DNA (daughter strand) during replication. Like many things, polymerase isn't perfect, so there is verification in DNA to check for mispaired nucleotides. If this verifaction finds any mutations, it is replaced and corrected from the daughter strand by using the parent strand, the one that is known to be correct to try again and make a the copy perfect. If DNA were 100% conservative and two daughter strands came together and one had a mutation, there would be no way to identify which is the “correct” strand and which is mutated.