UML represents the current state of the software model with the help of 13 types of diagrams. The methodology of modeling is usually described as a process of reasoning new properties of these diagrams on the base of their previous versions. There is not, however any formal support of remembering the trace of this reasoning process. The introduction of the vertical relation, showing how an element of one type of a diagram has influenced the creation of some elements belonging to other diagrams, seems to be very useful for software maintenance. The paper discusses the problem of such a vertical relation construction with the help of graph transformations. It shows its utility from technical and business perspective.