When a musical session is performed via networks, it is necessary to interact in real-time. There exists, however, the problem of delay between the nodes, which causes musical notes become an impediment. To overcome this problem, we had proposed a new protocol for musical session called Mutual Anticipated Session (M.A.S.), which is a type of ensemble that controls the appropriate timing of the sounds. In the M.A.S, one player's performance precedes the other players', so we call this performance "precedent musical performance", and we call the time lapse between the players' performance as "precedent time." In the current M.A.S, it is assumed that the tempo during the performance is constant. In a case, however, where players want to perform more expressively or more emotionally, they may change the tempo. Thus, in this paper, we add a function that accommodates the change of the tempo and evaluate the function experimentally.