I know this is an old topic but I've just suffered this frustration - again - and find it hard to believe that there is no way to add a new person to an existing tree without having an attached record in ancestry.com. In my case I have found the death certificate of a child with one of the parents' names missing and the other possibly misspelled. I'm not sure he belongs to the folks in my tree but there are enough other factors to make me want to add him. I should be able to do this without attaching him and detaching him from a set of parents.