A passivation method to passivate a given system by using an input-output transformation matrix is introduced. This matrix generalizes the commonly used methods of series, feedback and feedforward interconnections to passivate a system. Through an appropriate design of this matrix, positive passivity levels can be guaranteed for the system. Further, this transformation matrix allows the use of a non-passive system as a controller to guarantee the passivity and stability of a feedback configuration. We illustrate the results by considering systems with input/output delay.