How to convert Set into List in Salesforce?

Set<String> encounteredNames = new Set<String>();
Set<String> duplicateNames = new Set<String>();
for(String cd1 : listName) {
if(encounteredNames.contains(cd1.Name)){
duplicateNames.add(cd1.Name);
}else{
encounteredNames.add(cd1.Name);
}
}
List<String> newlistName = new List<String>(encounteredNames);