This paper presents an automatic speech transformation method of non-ideal phonation of speech (irregular or creaky voice). The irregular-to-regular transformation is performed by analyzing and resynthesizing the residual. A recent continuous pitch estimation algorithm is used for interpolating F0 in regions of irregular voice. The linear prediction residual of irregular sections of speech is replaced by overlap-added frames from a codebook of pitch-synchronous residuals. Finally, speech is reconstructed from the residual. A listening experiment showed that by transforming natural speech samples containing irregular voice, the perceived roughness of the transformed speech is decreased.