context: Reservations are essentially caveats to a state's acceptance of a treaty. Reservations are unilateral statements purporting to exclude or to modify the legal obligation and its effects on the reserving state. These must be included at the time of signing or ratification, i.e. "a party cannot add a reservation after it has already joined a treaty".
question: ఒక ఒప్పందం చట్టబద్ధమైన బాధ్యతలకు లేదా దాని ప్రభావాలకు ఏమి చేయడానికి ప్రయత్నించే వాక్యం దానిలో ఉండవచ్చు?
answers: exclude or to modify