This paper presents methods for the reconfiguration of a multicast tree at the instance of node migration in cellular wireless networks. We consider a novel and highly practical, formulation of the real-time multicast problem. Unlike the traditional notion of source to leaf node message transmission time being the measure for real-time, we consider the multicast tree re-construction time (in the event of a node migration) as the measure for real-time constraints. The overall goal is to minimize both the delays: i) delay of re-constructing the multicast tree and ii) source to destination transmission delay. In this paper, we introduce and provide solutions for the first objective, while the current research in real-time multicast tree considers the latter objective only. We propose two heuristics to solve the real-time multicast tree re-construction problem, one as a foreground and the other as a background algorithm, and present analysis and simulation results for several factors that contribute differently to the re-construction delay.