how to reset. ?

hello me and my gf move to a new place its got a Optima Alarm we have asked the land lord for the code so we can use it but he says he dont no the code as the bloke that lived here be4 us got it put in. is thay a way to reset it so that we can use it and i dont no if it still works the red light on the Detectors comes on when we move about and its got a green light on the box saying day then a red light saying power we have been here for over a year so dont no if its working or not thank you wayne.