Sentencing, Plea Bargains how to petition for a change in sentenceing

[kamrcs]

I am inquring on behalf of a inmate currently held in the peitentiray of new mexico. He has sentences that run consecutive which at best gives him a release date of 2045 it is our desire to try to get the senteces to run concurrent and to find someone to help. I am willing to do the research and filing if i knew where to start.