I do a retreive on an object like: Person[] persons = Person.FindAll();
then i pass an object ot a class like: class PersonProcessor{
private Person person;
PersonProcessor(Person p) {
this.person = p; //SOURCE OF ERROR
}

I make a call like:new PersonProcessor(persons[0]);

Due to that variable assigment I will always get a
Could not perform Save for Person-a different object with the same identifier value was already associated with the session: c2d00de1-65e8-464f-907f-d3eeeb9588b6, of class: Unicru.Persistence.BusinessObjects.Person

no matter what any subsequent method wants to do to the local person object. I think this is due to the fact the because of the Find() call all of those person objects are loaded into the session. okay, but why cant I assign a local variable to one of those persisted objects and act on it ?

If an instance of the "same" Person object (same ID) is already in the NHibernate session you're using to save the Person instance you pass to your PersonProcessor class, then your PersonProcessor class would need to either remove the "old" instance in its session using Evict(), or save the passed-in person using SaveOrUpdateCopy(). I think Evict() will hose things up by removing referenced entities from the session (probably not what you want), so try SaveOrUpdateCopy().