Maybe this is simpler than I realize, but at the moment it isn't obvious to me.
I'm trying to ADD a note to a user property without replacing it. In the possible options for updating a user, one can only remove the property/value, or replace the value.
The example here is that I want to append a note to whatever currently exists in the notes field, not replace it. So, if I change the name of user, Adaxes will update the notes field with the current date time stamp with this custom note. All of the existing information remains inside the notes field.