  We study the dispersion of the $\pi$ resonance in the superconducting state
within the projected SO(5) model\cite{project}. Away from the the commensurate
momentum, the propagation of the $\pi$ resonance creates phase slips in the
superconducting order parameter. This frustration effect leads to a strong
dressing of the $\pi$ resonance and a downwards dispersion away from the
commensurate wave vector. Based on these results, we argue that the the
commensurate resonance and incommensurate magnetic fluctuations in the cuprates
are continuously connected.
