Gothic 3 Enforcing quest parameters

I assume that the game is keeping track of a whole load of parameters to determine what you have done or not. Due to it's bugged state it might be good to know if it's possible to change parameters through the MARVIN console, making the game "forget" what you have done or not by force-change theese parameters.

Used to you could use Marvin to reset NPC states by Highlighting them then doing an Edit, but since I can't use the Console I don't know now.

I only know how to see the parameters, not how to change them.