Board Thread:Administrative Requests/@comment-24573226-20160522025838/@comment-3146930-20160522031232

But you could also write it as James' dog because his name ends in an S. If James' sister was named Mary and she was given the dog, it would be Mary's dog. There isn't a concrete rule saying you need to add that ending S, but you can or you can't; depends on the person really.