When we carry out planning to make arrangements, we may reach some point in dispute in planning because of physical obstacles and/or logical contradictions. When we concerned with mechanizations for adjustments of planning proposals at meeting, we are motivated to formulate the point in dispute and its dissolution with reference to space and time descriptions in proposals. In this sense, we take the situation theory presented by J. Barwise as the basis. Making use of the situation theory, we formally define the point in dispute from logical conflict, timing and spatial problem viewpoints. To do so, we present the idea of situation model which represents a set of situations supporting an infon [Barwise 89]. We take the notion of dual infons, which represent a logical inconsistency, time or space conflict. The point in dispute reflects the existence of dual infons. By means of dual infons, we firstly define the point in dispute of the situation model, and next present a method to dissolve the point by removing the set of situations, expressed in terms of the situation models, which support the point in dispute. Three kinds of points in dispute are introduced, being discussed in a unified way so that they may be dealt with in Lisp and be dissolved.