What difference between Revert and MarkAsClean methods.

[BekAllaev]

public PersonProxy TempPerson
{
   set { Set(ref proxyPerson, value); }
   get { return proxyPerson; }
}

PersonProxy inhereted by ValidatableModelBase. I were thinking about how I can set IsDirty to false if TempPerson become dirty. And have solved this by MarkAsClean method but at the same time I have noticed that Revert method also may change IsDirty value to false. So when I used breakpoint and checked value of TempPerson properties after I have called MarkAsClean and made same action for Revert method and I saw that only thing that this methods do is changing IsDirty property, while other properties stay the same. So the result of this methods I can see by the situation that I have described before so explain me please what this methods must to do cause there must not be two methods that do the same procedure.

[JerryNixon]

Revert returns the Value to the OriginalValue.
MarkAsClean sets the OriginalValue to the current Value.