This Order enables courts to vary orders and agreements in personal injury cases under which all or part of the damages take the form of periodical payments. Articles 2 and 9 restrict the circumstances in which variation is permissible to those where there is a chance that the claimant will develop some serious disease or suffer some serious deterioration, or enjoy some significant improvement, in his physical or mental condition, and the court has ordered, or the parties have agreed, that the order or agreement is to be capable of variation.