How can I use a function with a circuit?

Hello, I would like to take the output voltage from a circuit I made in simulink and then manipulate through an equation. Then I want the output of this equation to act as a voltage so I can feed it into another part of my circuit? How can I do this? I essentially want to take the output voltage of the circuit, multiply it's magnitude, shift it's phase and then use this new number as a voltage elsewhere. It's just like a transformer, however I can't seem to get a single phase transformer to connect with my circuit.