A motion to revise and revoke is a motion entered by either the sentencing judge or the defendant requesting that the sentence handed down to the defendant is changed because justice was not done. While many judges interpret this Massachusetts rule rather broadly in order to modify existing sentences due to a wide variety of circumstances, Massachusetts appellate courts have been less likely to extend the rule. According to the appellate courts, the purpose of this rule is the permit a judge to reconsider the sentence imposed and determine looking at the facts that existed at the time of sentencing, whether or not the sentence was just. Looking at this strict definition, actions of the defendant after sentencing, such as good behavior while incarcerated, cannot be considered by a judge in a motion to revise and revoke. In the view of the appellate court, to allow judges to consider conduct of the defendant after the sentencing circumvents the role of the parole board, which is a power assigned to the executive branch. If it appears that a judge interfered with the parole board's function, the appellate court will almost always overturn the judge's decision.
A motion to revise and revoke can either be filed by the defendant or the judge, but both must adhere to the strict 60-day time limit imposed by the law. No matter the circumstances, the 60-day time period cannot be waived and cannot be waived by an agreement between all parties. While there is a time limit for filing the motion, it is rare that the motion is actually heard and decided within that period. In addition, while a defendant typically files the motion in hopes of having his sentence reduced, it is always possible that the judge increases the sentence. The only requirement for changing the sentence is that justice was not properly served the first time around.
In order to file the motion, the defendant must file an affidavit in support of the motion with all the relevant information. The affidavit must include the grounds to the allowance of the motion and show that the grounds addressed are proper for granting the motion. Once this is done, the prosecutor has the option to submit a response to the motion.
Once the motion is filed, like all other motions it must be heard by the court. The sentencing or trial judge will hear the motion, and both the defendant as well as the prosecutor has a right to appeal a decision of the judge. In the hearing, the court can consider the sentence's effect on a number of different areas of the defendant's life. The judge can consider the defendant's job, family, health, and immigration status. In contrast, the judge cannot consider whether or not the defendant had good behavior while incarcerated or whether or not the defendant was granted parole. Once heard, the judge will rule on the motion and can change the defendant's sentence as he or she sees fit. 
MCLE Crime and Consequence § 20.3
ALM R. Crim. P. Rule 29
Dana A. Curhan, Motions to Revise and Revoke Under MASS. R. CRIM. P. 29: A Quick Overview, http://www.criminalappeals.com/ReviseRevokeArticle.html.