We study the semi-holographic idea in the context of decaying dark components.The energy flow between dark energy and the compensating dark matter is thermodynamically generalized to involve a particle number variable dark component with non-zero chemical potential.It is found that,unlike the original semi-holographic model,no cosmological constant is needed for a dynamical evolution of the universe.A transient phantom phase appears while a non-trivial dark energy-dark matter scaling solution stays at a later time,which evades the big-rip and helps to resolve the coincidence problem.For reasonable parameters,the deceleration parameter is well consistent with current observations.The original semi-holographic model is extended and it also suggests that the concordance model may be reconstructed from the semi-holographic idea.