illegal sentencing Sentencing, Plea Bargains

my husband was sentenced last july for 4 different crimes which we consolidated infront of the same judge to be heard at the same time. at the time of his trial he was found guilty and the was sentenced 18 months to run consecutive to 18 months to run consecutitve to 18 to run concurrent with an 15 month sentence. I have been doing some research and i believe i have found that under the maryland law we can ask the judge to ammend this for one judge is not allowed to run his sentencing the way she did? i am wondering what we can do about this please feel free to help with some legal advice or where i can look for such information, we need the help plz... thank u..