MusePack audio files (.mpc) can be converted to a broad range of other audio formats, including .flac. However, this will not be much of use, because FLAC is used for lossless compression quality and MPC format is already lossy, hence your quality won't improve and you will probably get much large file sizes. So is mpc to flac conversion is possible, but useless.
Updated: November 18, 2022