user defined multiplier function to change the parameters of a simulink block through a simulation time

Dear community memebers,

I want to simulat a 24hr(daily simulation in phasor) load profile in simulink. For the snapshot simulation I have drag and drop the constant RLC load (I can specify the P and Q variables there) and later want to use a stochastic simulation.How could I change the values of P&Q for daily simualtion dynamically.